This PDF file contains the front matter associated with SPIE Proceedings Volume 12722, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

Photovoltaic industry has become an important development industry in Yuanmou County. In order to obtain the suitability of the site selection of the solar photovoltaic energy power station in Yuanmou County, this paper selected eight factors including solar radiation, temperature, land use type, road, elevation, distance from residential areas, slope, and aspect to construct the site selection suitability evaluation index system, and used buffer analysis, solar radiation analysis, reclassification, superposition analysis methods to evaluate. The results showed that the top three areas with the highest proportion of the most suitable areas were Yangjie Town, Liangshan Township and Xinhua Township; the most suitable areas were mainly located in the north of Jiangyi Township, the south of Jiangbian Township, the west of Wumao Township, the west of Pingtian Township, east and west of laocheng Township, most of Xinhua Township, Liangshan Township and Yangjie Town, The research results will provide theoretical basis and decision support for the site selection of photovoltaic energy power stations in Yuanmou County, and can also provide research cases for related regions.

After tunnel construction completion, it’s difficult to ensure the drying tunnel due to the distribution of rock joint fractures and confined water. Usually, the pipeline operation in underwater tunnels is filled with water. In this article, it collected some serious pipeline displacements, pipe deformations, and bolts falling off during the later operation of an oil and gas pipeline tunnel. It uses the finite element calculation method according to the actual working conditions of the pipeline installation to simulation of the pipeline state taking consideration of the combined factors such as internal pressure, temperature difference, water buoyancy load, and collar constraints. Three operation conditions of water filling operation, pumping inspection and refilling are considered, and simulation calculations are performed. The calculation results show that although the pipeline is in a safe stress state, but the bearing bolts near the pipe elbow have excessive stress. The results of numerical calculations explain the cause of the problem, and put forward suggestions for pipeline repair as a basis.

The ocean contains rich and clean renewable blue energy such as wave energy, tidal energy and temperature difference energy. Wave energy, as one of the cleanest renewable energy sources, has the advantages of wide distribution area, long utilization time and huge energy reserves, etc. If the waves in the vast ocean can be used rationally, it can greatly satisfy human energy demand and reduce CO₂ emission, and bring profound changes to the world energy pattern and affect all aspects of economy and society. In this paper, we report an Orbital-Train Triboelectric Nanogenerator (OT-TENG) that can collect wave energy in all directions, which consists of a "rail" and a "train". The waves give a push to the train, and the train runs in the track in constant contact with the friction layer on the inside of the track to obtain electrical energy. With a 30° wave push, the OT-TENG can reach a stable voltage output of 100V, a current output of 2.3μA, and a maximum power output of 57.6μW. It can provide electrical power to electronics by charging capacitors. The wave energy on the ocean surface is abundant, and the OT-TENG can operate for a long time to generate electricity. This study shows that the OT-TENG can collect wave energy in all directions, which breaks the directional limitation of existing TENGs and provides a clear direction for the subsequent blue energy harvesting TENGs.

The mechanical properties of the whole machine tool directly affect the machining quality of the machine tool. Firstly, the stiffness matrix of gantry machine tool foundation system is assembled by using beam element. Secondly, the mechanical analysis of system model under arbitrary load is realized by using EXCEL. Once more, it is proved that the theoretical model has high accuracy through the application of ANSYS software simulation. Finally, based on the theoretical model, the influence of the foundation on the machining accuracy of the machine tool is analyzed. This method can simply and quickly realize the mechanical analysis of complex systems, and has high application value and popularization.

The magnetohydrodynamic momentum ring studied in this paper is used for satellite attitude adjustment. The purpose of this paper is to study the magnetic field distribution characteristics of magnetohydrodynamic momentum ring. In this paper, the coupling method is used for numerical simulation. The results show that the design of axial magnetic field distribution is more reasonable. The simulation results can be used to provide reference for the subsequent experimental research.

In this paper, the cause of the fracture failure of lifting wire rope in an elevator installation accident is analyzed. By analyzing the macro and micro morphology, metallography, tensile test, simulation calculation and chemical composition of the wire rope fracture, the fracture failure reason of the wire rope was determined. The results show that the reason for the fracture of the steel wire rope in this elevator installation accident is overload fracture failure, which is mainly related to the improper layout and use of the steel wire rope, resulting in the load borne by the steel wire rope exceeding its minimum breaking force.

A new form of lifting equipment machine that can achieve automated unhooking and has a self-balancing function is devised in response to practical issues like the intricate lifting operation process and potential safety dangers connected with the existing lifting tools. To realize the completion of automatic unhooking, the safety performance of the key components should be guaranteed, so the static analysis of the dial rod is conducted using ANSYS Workbench software, in order to properly and efficiently determine the load of the push pole. The analysis results favorably support the push pole's actual load capacity, make it easier to optimize structure later on, make the design more logical.

Four temperatures, four pressures and two flows are included necessarily in one whole operating condition for a heat exchanger, and they influence each other. They are also essential to calculate and report heat capacity Q and overall heat transfer coefficient k. It is important for Monte Carlo method to investigate different models of production of mass random data. In the present work, an input model of a uniform distribution was compared with that of a normal distribution for the same heat exchanger under the same reference operating condition. They were employed independently and respectively to produce 100,000 sets of random operating conditions on the base of a real test result. Though input temperature and pressure were both subject to the uniform distribution, the specific heat, density, thermal conductivity and fluid viscosity of the tested fluid did not necessarily follow a uniform distribution. The comparison showed that calculated Q, k and other relative parameters all were subject to the normal distributions; furthermore, the input model of normal distribution gives out the measurement uncertainty of 7374W, 58 W/ m2·K for Q, k, while that of uniform distribution lead to the measurement uncertainty of 7361W, 58 W/m2 K, respectively. Obviously, the difference is less than 1%, therefore they are considered to create the same measurement uncertainty for heat exchanger.

The magnetohydrodynamic momentum ring for satellite attitude adjustment is studied in this paper. The aim of this paper is to research the fluid field characteristic distribution in the magnetohydrodynamic momentum ring. The numerical calculation results indicate that liquid metal can produce effective rotational flow under the action of electromagnetic field. The numerical results show that the fluid ring design is effective and achieves the design expectation, and it can provide reference for the future experimental tests.

Structured surfaces play an essential role in reducing surface drag. In order to obtain the drag reduction performance of structured topological fish scale surface, the computational fluid dynamics theory was used to analyze and study. First, the parameters of the fish scale surface are designed by topology. The fluid model of the surface is established, and the CFD software ANSYS Fluent numerically analyzes the surface. The variation regularity of the surface's friction coefficient in different areas is studied, and the drag coefficient of the surface is analyzed. The research shows that the variation and fluctuation of the surface's friction coefficient are different in different areas. The drag reduction ability of the structured topology fish scale surface is better than that of the fish scale surface, and the best drag reduction effect of the structured topology fish scale surface is about 5.36%.

The investigated magnetohydrodynamics liquid ring is applied to space missions about satellite attitude control in this article. The magnetohydrodynamics liquid ring physical equipment was tested, and the fluid velocity and current were measured. The experimental results display the liquid ring is workable with attitude adjustment task control. The experimental results offer data basis about the futural optimization design on magnetohydrodynamics liquid ring.

The traditional manual measurement technology of corrugated plate structure parameters of plate heat exchanger is timeconsuming, large error and unstable reliability.The non-contact measuring device based on laser scanning sensor is developed, and the test test verifies the reliability and scientificity of the device, and then the test results and error are quantitatively analyzed.The results show that,digital measurement technology of non-contact measuring device based on laser scanning sensor,is the innovation and optimization of the traditional artificial measurement technology,It can efficiently and accurately measure the structural parameters of the corrugated plate.

In this paper, a liquid nitrogen zero boil-off (ZBO) system is designed for the detection of high-purity germanium(HPGe). The system has the characteristics of lightweight, low heat leakage, and high intensity. Its no-load static evaporation rate is 0.12L/d, which is about 50% of the traditional biological container. When simulating the heat leakage of 1L/d of HPGe detector, but the actual 0.69L/d, the system's static evaporation rate test data is about 0.78L/d, and the relative error is about 4% with high consistency. Therefore, when the actual 1L/d heat leakage, the total heat leakage is about 1.2L/d, which is 30%-40% of similar products, and the performance is greatly improved. The system controls the output power of the refrigerator through the change of pressure. With the special air duct, the performance of the refrigerator is improved, and the high performance of ZBO is realized, which provides the necessary conditions for the continuous detection of HPGe.

Recently, reduction gearbox is a kind of general components which is widely used in marine engineering equipment, and generally under the premise of enough carrying capacity and scheduled life, reliability is the main aim of its design and manufacture. However, the higher reliability always brings the higher mass and cost for the manufacturer, which brings a contradiction between reliability and cost of the gearbox. So it is of great significance to find a balance between reliability and mass of the gearbox to realize the best cost performance. In this paper, an optimization model of a parallel shafts gearbox is built, whose optimization objectives are both mass and reliability. By adjusting the weighting factors of each objective function, a relation curve between the least mass and the highest reliability was obtained. And finally the economy and reliability of the gearbox can be coordinated by analyzing the curve and finding the inflection point, at which a relatively maximum reliability and minimum cost can be achieved. This way may be an effective one for gearbox design that may provide guidance for similar engineering problems.

Taking lithium titanate battery as the research object, the internal resistance of starting battery was studied. Effects of four stresses on DC internal resistance of battery were investigated and discussed based on the battery test system, which were charging rate, discharge rate, state of capacity and temperature, respectively. The results show that the increase of charge/discharge rate leads to the reduction of DC internal resistance when the battery SOC is in the range of 0~90%, but these DC internal resistance values are close. The DC internal resistance is greatly affected by the temperature, the smaller DC internal resistance appears at the higher temperature. The DC internal resistance values of 0~90% SOC can be used in the process of starting power supply design for simulation processing.

Scanning system is the key system of scanning optical remote sensor. The scanning system pursues high angle measurement accuracy, high control accuracy and high efficiency. The key technologies mainly include scanning mirror and lightweight technology, high precision angle measurement, high precision drive motor, high reliability shafting, low noise angle measurement and control circuit. A new scanning system with high reliability and high precision is presented in this paper. The selection of scanning mirror, shafting, motor and angle sensor, the scheme of scanning control are introduced. A dynamic angle measurement error test and compensation method is introduced, and the influence of space environment on angle measurement accuracy is analyzed. The angle measurement accuracy of space application is better than 1 arc second.

This paper introduces the basic principle of measuring the axial stress of optical fiber based on Brillouin time domain analysis technology (BOTDA), and applies distributed optical fiber sensing to the axial stress monitoring of power cables. We build a cable axial stress monitoring system based on BOTDA, and in view of the problem that the built-in optical fiber structure of the existing optoelectronic hybrid cable could not be effectively used for stress monitoring, we propose a new type of intelligent sensing cable. The built-in optical fiber adopts a nylon tight-packed structure, so that the force on the optical fiber can effectively represent the axial stress of the cable. We build the Brillouin frequency shift test platform to study the influence of different bending radii on the Brillouin scattering frequency shift of optical fibers when the cable was bent. The test results show that the built-in optical fiber of the cable adopts a nylon tight-packed structure, and combined with BOTDA technology, the stress distribution of each position of the cable can be effectively monitored by analyzing the Brillouin scattering frequency shift, which can reflect the axial stress of different bending radii of the cable. It provides strong support for establishing a cable stress database and building a comprehensive perception platform for power cables.

In order to solve the problem that the operational characteristics of the boom after the boom potential energy recovery system(BPERS) is adopted in the hybrid hydraulic excavator are reduced, aiming at the electrical BPERS, A compound control strategy is proposed to control the speed of the hydraulic cylinder of the boom by the throttle valve without pressure compensator and to control the target torque of the hydraulic motor - generator unit(HMGU) by the pressure difference between the inlet and outlet of the throttle valve. Then establishing the mathematical model of the system and analyzing the frequency response of the system. Finally, the AMESim software is used to simulate and analyze the BPERS. The results show that the control method of the BPERS is feasible. The method can not only realize the recovery of the boom potential energy, but also improve the operation characteristics of the excavator boom system.

A model to forecast chatter in surface grinding is proposed considering the stiffness variation along the longitudinal direction, which is suitable for beams with different kinds of constraints. Utilizing the method for stability analysis of control systems, the stability condition of the grinding system is obtained. According to the results from the model, the probability of chatter increases with the distance from the constraint under the same grinding condition. The stability limit curve (lobe diagram) at any position in the longitudinal direction could be acquired from the model, which can provide evidence for chatter avoidance. The stability diagram expresses a parameter space between the speed of the spindle and the nominal grinding depth, where the grinding process is stable using the parameters below the stability curve but unstable using the parameters above the stability curve. In this paper, grinding of a simply supported rail beam is taken as an example. The chatter forecast is verified via rail beam grinding.

Due to the diversity and complexity of the causes of the heating failure of the hydraulic system, it is extremely difficult to trace the source of the on-site diagnosis. Taking the heating failure of the hydraulic system during the jacking process of a certain tower crane as an example, the virtual fault information obtained from the fault tree analysis is injected into the thermal fluid simulation model of the tower crane jacking hydraulic system, and the influence characteristics of the virtual fault on the system pressure and oil temperature are obtained. The fault diagnosis is realized by comparing with the temperature rise curve of the fault hydraulic system on the test bench. The research results show that the fault characteristics caused by the lowering of the set pressure of the relief valve are highly consistent with the test results, so it is determined that the overflow caused by the lowering of the set pressure of the relief valve is the main cause of the system heating fault, and the fault can be solved after on-site adjustment. The virtual simulation method of hydraulic system based on fault injection can effectively reproduce the real fault characteristics of hydraulic system and provide necessary reference for fast and effective fault diagnosis of complex hydraulic system.

After the short-circuit fault occurs in the subway DC power supply system, the traditional manual line patrol troubleshooting method not only takes a lot of time and effort, but also increases the workload in today's subway system with the increase of lines. The system becomes more complex, resulting in longer power outage time and unnecessary economic losses. In this paper, the improved genetic algorithm is adopted to solve the metro fault location. The optimal solution of the short circuit fault calculated by the single-ended genetic algorithm is solved by the genetic algorithm every time. Although the solution converges to a certain value, the value is not the same every time, it fluctuates back and forth in a certain range. By setting a reasonable threshold, the fault can be identified quickly and accurately. The reactance voltage drop of the fault pole is significantly greater than that of the non-fault pole. The obtained optimal solution of the short-circuit fault position can quickly and accurately determine the fault position, so that the fault recovery time can be shortened. The operation efficiency can be improved, which is of great significance for ensuring the safe operation of a power supply system.

Nowadays, the world is facing the threat of energy exhaustion. In order to realize the maximum utilization of energy, this paper designs an organic Rankine cycle system for low-temperature waste heat generation. Firstly, the equipment and components in the organic Rankine cycle system are modeled. Secondly, combining specific analysis, designed the low temperature waste heat power generation organic Rankine's circulatory system, and analyses the relevant evaluation index, performance or independent variables is studied the effects of main parameters on the system performance, and finally, in finite time thermodynamic analysis method, analyzed the unit of each independent variable parameters on the heat transfer area of the influence of output power. It provides a powerful basis for the design of the system and the improvement and optimization of its performance. The simulation results show that the system designed in this paper can effectively recover waste heat from waste gas and realize the function of power generation, which has a certain practical value.

Monitoring and measurement on footing resistance of transmission towers is an important safeguard to transmission towers. This paper introduces a frequency conversion measurement technology that greatly increasing efficiency and accuracy of measurement on footing resistance of transmission towers. The study analyses the technology of device's hardware and software systems, and the application result shows that the device helps easier and more accurate monitor transmission towers grounding resistance.

The uniformity of gold plating of 6-inch wafers in conventional sulfate plating solution was studied by numerical simulation technology. The effects of current density, cathode and anode distance and baffle distance on plating uniformity were studied to obtain the gold plating layer with the uniformity of less than 5%. The results show that when the distance between the cathode and the anode is set to be 15.5 cm, and the distance between the baffle and the cathode is 4.5 cm, when the current density is 5-15A/m², the uniformity of electroplating gold is less than 5%, which meets the production requirements.

Despite great progress in transient stability assessment (TSA) using machine learning-based approaches, one still cannot seamlessly relate data-driven TSA methods to the dynamics of post-disturbance systems. Uninterpretable black-box decisions neglecting the inherent physics information are typically unacceptable in the power industry. A physics-informed machine learning-based method is proposed to predict the post-disturbance trajectory, where the differential-algebraic equations governing physical characteristics are introduced to guide the training process. Then, a novel TSA framework is developed that combines the system stability results with the predicted post-disturbance trajectories, where the stability margins and the stability judgments can be provided simultaneously. Moreover, a physics-informed metrics is introduced to reflect the accuracy of TSA, which can be obtained immediately without performing time-domain simulation. Finally, the effectiveness of the proposed method is verified on the IEEE 39-bus system.

Three-dimensional numerical simulation of two-phase flow (H2O2 solution, NO2) was carried out on the packed rotor inside the multistage high gravity machine by using Fluent software. At the same time, the chemical reaction process of H2O2 solution and NO2 was added to realize the simulation of the denitrification process. Orthogonal experiments were designed to study the influence of rotating speed, gas-liquid ratio, temperature, and H2O2 solution concentration on the denitrification efficiency, and the combination of experimental conditions with the best denitrification efficiency was obtained. The simulation results show that the order of effect on removal efficiency is: rotating speed<gas-liquid ratio<temperature<H2O2 concentration; Under ideal conditions, the removal efficiency of NO2 is high when the rotating speed is 900 rpm, the gas-liquid ratio is 10:1, the temperature is 30 ℃, and the concentration of H2O2 is 0.2 mol/L. It provides theoretical data for the practical engineering application of multistage high gravity machine and has guiding significance.

At present, when artificial intelligence algorithm is used to predict the hot spot temperature of oil-immersed air-cooled transformer, the selection of the input characteristic quantity of the prediction model is not accurate enough and the prediction accuracy is insufficient. Based on the analysis of the internal temperature rise and heat dissipation process of the transformer, the tank wall temperature of oil-immersed air-cooled transformer is taken as one of the input characteristic quantities in the prediction model, an ant colony algorithm optimized support vector machine (ACO-SVM) model for predicting transformer winding hot spot temperature is established. Taking the measured data as a sample, the prediction performance of the model in this paper is compared with the PSO-SVM model and the SVM model, indicating that the proposed method has higher prediction accuracy and better applicability for predicting the hot spot temperature of oil-natural air-forced transformers.

In this paper, based on load prediction, flexible resources such as load storage and other aspects of the source network are comprehensively considered, and the total load curve, net load curve, natural peak clipping curve, grid side peak regulation curve, balance curve and power demand are obtained through superposition of electric energy replacement load and conventional load. An innovative power balance method and process for collaborative planning of source network charge and storage for new power system is proposed to help the construction of new power system.

Reducing energy consumption caused by automobile fuel is an important issue in new energy and energy saving research. Vehicle wind power generation technology can decrease the vehicle non-natural wind energy waste and achieve energy saving and environmentally friendly vehicles. The ducted flow field and pressure field were simulated by the finite element analysis modelling ANSYS to study the influence of the opening tuyere on the vehicles forepart on the energy saving with the drag coefficient as research index. The results showed that the drag decreased during driving with the windward area decreasing and the more uncorking coefficient (Cd) the less drag coefficient. What’s more, drag coefficient decreased by 15% when the ratio of the pipeline diameter and vehicle front-end height (d/h) was more than 0.6. The drag coefficient decreased linearly with the increase of the uncorking coefficient approached a limit value when Cd was more than 0.6 in the vehicle dynamic system of wind and electricity.

Multi energy flow coupling, such as electric heating and cooling, is an important feature of integrated energy system. Aiming at the uncertainty of source load caused by the deviation of wind and solar output prediction and load growth prediction in the optimal configuration of multi energy flow system, an optimal configuration method of electric heating and cooling multi energy flow system considering the uncertainty of source load is proposed. Firstly, the physical mechanism and characteristics of the key distributed energy equipment and energy supply network in the multi flow energy supply network of the energy hub are analyzed; The information gap decision theory is used to deal with the prediction deviation caused by the increase of electric heating and cooling air load in the model, and the conditional risk value theory is used to adjust the modeling scheme to assess the risk loss caused by the wind and solar power output prediction deviation. The example analysis shows the optimal allocation results of the deterministic model and the model taking into account uncertainty. The comparison with other optimal allocation methods verifies the effectiveness and superiority of the method in this paper. At the same time, it analyzes the impact of the changes in the avoidance coefficient and risk coefficient in the model on the model results and investment strategies, which proves that the model has the ability to quantify and evaluate the output uncertainty on both sides of the source load.

Aiming at the sudden short circuit of three-phase power transformer, some structures of the transformer are reasonably simplified to establish a three-dimensional finite element field-circuit coupling model of the transformer, and the dynamic response of the transformer under three-phase symmetrical short circuit is analyzed by Maxwell transient electromagnetic field simulation. The short-circuit current of the transformer reaches its peak value at 0.0092s at the beginning of the simulation, that is, the inpact current is 14645.8 A, and the distribution of the axial and radial leakage magnetic fields is obtained. Based on this, the electromagnetic force of the winding during short-circuit is calculated.

In order to identify the impact cooling ability of liquid nitrogen (LN2) on difficult-to-machine materials, the Computational Fluid Dynamics (CFD) was used to simulate the impact cooling state of LN2 on titanium alloy. The results show that the diffusion direction of LN2 is wider and the effective cooling range is larger at a little injection angle. When the injection speed (flow rate) is larger, it is followed the lower cooling temperature and the larger cooling depth for titanium alloy. This study reveals that LN2 jet angle and impact velocity can play an important role in the cooling effect for titanium alloy components, and can provide a theoretical reference for difficult-to-machine metal workpieces based on LN2 cryogenic cooling.

Mechanical parking system has been widely used，but there is no systematic inspection for the program logic of the control system software and the reliability of the hardware. To solve the problem, a real-time simulation system, based on dSPACE has been established, as well as modular simulation models. Through the test, it is proved that the simulation system can provide a near-real software and hardware test environment for the controllers of various types of mechanical parking system for the logic verification of the control system program and the reliability test of the hardware.

The steam-type high-temperature solid thermal storage system is a kind of thermal storage and steam supply system, which can store surplus power in the heat storage regenerator and use it to produce steam when needed. A dynamic model for the steam-type high temperature solid thermal storage system is proposed using Matlab/Simulink. The dynamic characteristics of the above system are analyzed under the conditions that the inlet air volume and outlet air temperature are kept constant. And the response curves of the main parameters of the system, such as the load of users and outlet air temperature, with the change of operation time are obtained, which reveal the dynamic characteristics of the steam-type high temperature solid thermal storage system.

In the high-speed motorized spindle rotor system, the running accuracy and stability of angular contact ball bearings are significantly affected by temperature rise. In order to obtain a more accurate transient temperature field of angular contact ball bearings, a heat generation and heat transfer model considering spin was established, and the heat generation of the bearing was obtained by using MATLAB software, and then the factors affecting heat generation were studied, and at the same time, the Thermo-mechanical coupling finite element analysis was carried out on the LS-DYNA platform based on the explicit dynamics. The research results show that: the rotational speed is the main factor causing the temperature rise of the bearing; The greater the axial force, the more heat generated; at high speed, the heat generation is more sensitive to the increase in the axial force; The heat generation increases as the viscosity of the lubricant increases, which indicates that more energy is lost by the viscosity of the lubricant. The research can provide theoretical guidance for bearing design and stability analysis in high-speed rotor systems.

The continuous rise of the maximum load of air conditioners in the extremely high temperature weather of summer has brought a significant challenge on the power supply. The development of cooling system with photovoltaic and ice storage can play an important role. In this paper, a research on the optimal capacity configuration of the cooling system with photovoltaic and ice storage is carried out. Aiming at the lowest cost per unit of cooling capacity, the time-of-use electricity price, ice storage capacity and the maximum cooling load are considered to formulate an operation strategy. Under a given typical daily cooling load curve and photovoltaic output curve of a certain building, the influence of photovoltaic capacity and ice storage capacity on the cost of unit cooling capacity is analyzed. The case study shows that the optimal photovoltaic capacity is generally not affected by the cooling and ice storage tank capacity, and there is also an optimal value for the ice storage tank capacity.

In order to study the influence of the impedance matching and thickness distribution of the separator material on the impact initiation characteristics of the charged charge in the double-layer separator test, this paper uses a combination of theory and numerical simulation, and takes the two-layer separator of tungsten alloy and aluminum alloy as the research object. Based on the theory of detonation physics, the shock wave pressure, particle velocity, action time and shock wave energy model of the shock wave propagating to the delivered charge after the detonation of the main charge is attenuated by the tungsten alloy and aluminum alloy two-layer partitions are established. Theoretical and numerical simulation studies the influence of the total thickness of the partition (18mm~35mm), the order of the partition and the thickness distribution on the impact initiation characteristics of the charged charge.

The finite element software FLUENT was used to study and analyze the flow characteristics of indoor particle concentration distribution in upper air supply buildings under different air supply parameters. Physical model and finite element model were established to calculate the concentration distribution of particulate matter, and to find the best air supply parameters and working conditions, so as to improve indoor air quality and comfort. Through the simulation calculation of indoor air flow field distribution and concentration distribution of fine particles under different working conditions, the optimal air supply parameters are obtained, that is, the temperature of the air supply outlet is 20℃, and the air supply velocity of the air supply outlet is 3m/s. The simulation calculation results in this paper provide certain design basis for determining the optimal air supply parameters in the subsequent reengineering.

In the complex electromagnetic environment of the transmission line, a large number of electromagnetic sensitive components in the control system of the live working robot cannot work stably and reliably. Therefore, aiming at this problem, this paper takes the 110kV transmission line live working robot as the research object, and conducts electromagnetic analysis and protection design for it. According to the three elements of electromagnetic interference, a solution to the electromagnetic protection of live-line working robots is proposed. In order to realize the live working of the robot, the equipotential mode is selected as the working mode of the robot, and the feasibility of the equipotential mode is verified through experiments.

There is strong electromagnetic coupling in DCTL (double circuit transmission lines on the same tower), especially strong zero-sequence mutual inductance, which leads to the fact that the fault location error of the single-ended single-circuit line configuration for distance protection is large. The existing method, which cannot fundamentally eliminate the influence of zero-sequence mutual inductance of adjacent lines, estimates the zero-sequence current of adjacent lines instead of collecting voltage and current of adjacent lines directly. Therefore, a single-phase grounding fault location method for DCTL that based on Newton iteration thought is proposed. This method uses Newton iteration method to improve the zero-sequence current estimation accuracy of adjacent lines, and the location of single-phase grounding fault can be calculated accurately only by using the electric quantities of single circuit line. The PSCAD/EMTDC simulation verifies the effectiveness of the method.

The downstream of a pumped storage power station is equipped with an impedance surge chamber, and the tailrace tunnel is connected with the connecting pipe through bifurcated pipes and bends. The layout type is special, and the water flow conditions are complex. Considering the complexity of the layout of the impedance surge chamber with long connecting pipe and the actual situation of engineering construction, this paper studies the flow pattern and flow coefficient at the bottom of the surge chamber under the typical layout. The variation laws of flow velocity distribution, pressure distribution and inlet and outlet flow coefficient at the bottom of the surge chamber with different layout schemes are obtained.

Energy storage, as a schedulable resource, can be added to the optimal scheduling model of microgrids, which can effectively improve the penetration rate of renewable energy in the grid and improve the reliability and economy of the system. Aiming at grid-connected microgrids, including wind power, photovoltaic, energy storage devices, and micro gas turbines, this paper takes the lowest comprehensive operating cost as the objective function. It takes power balance, distributed power output characteristics, energy storage battery power, and tie line constraints as constraints to establish the optimal configuration model of the microgrid. The Tent chaotic mapping and Cauchy mutation operator method improve the traditional algorithms of the grey wolf, such as the last use of an improved algorithm to solve the model; the simulation results show that the improved grey wolf algorithm has good optimization ability, this model can realize economy optimal micro power grid, the effectiveness of the proposed method was verified.

Aiming at the problems of poor design data traceability, low model reusability, and lack of overall system design concept during the development of the traditional Electric Multiple Unit (EMU) bogie instability detection system, we are applying the Model-Based Systems Engineering (MBSE) to the EMU bogie design of the instability detection system. Based on the Arcadia modeling method, combined with the function definition analysis method, the structure of the EMU bogie instability detection system is designed: the instability detection system is established through four levels of operational analysis, system analysis, logical architecture analysis, and physical architecture analysis. The architecture model from "black box" to "white box"; the function is defined and analyzed through three links: identification function, expression function, and evaluation function. The research shows that in the process of designing the structure of the bogie instability detection system for the EMU, the model established by the model-based systems engineering method is traceable and reusable, and the overall design of the system can be carried out in the early stage of creation, and the EMU can be improved. The research and development of the bogie have a favorable driving effect.

With the continuous development of automotive driving automation, scenario-based automated driving test evaluation methods have become an industry consensus. However, in terms of scenarios, the industry still relies on the subjective experience of experts to formulate evaluation plans, lacking scientific and quantitative evaluation methods, resulting in the problems of limited scenario coverage and low testing efficiency, which affect the mass production process of products. Therefore, this paper proposes a scene complexity evaluation method based on analytic hierarchy process (AHP) and information entropy theory, which realizes the automatic quantitative evaluation of test scene complexity and makes up for the lack of theoretical research on industry test scene. Finally, the method proposed in this paper quantitatively analyzes the complexity of typical scenarios in the Autonomous Driving Evaluation Project of CATARC, summarizes the key factors affecting the complexity of the scenario, and verifies the feasibility and effectiveness of the method.

In order to analyze the quality distribution of behind-armor debris and explore the source of debris, experimental and simulation studies on vertical penetration of armor steel by explosively formed penetrator (EFP) were carried out. With the help of experimental and verified simulation methods, the results were analyzed under different target thickness (10- 70 mm) and different EFP target hitting speed (1650m/s~1860m/s). After a typical EFP penetrates armor plate vertically, the quality distribution of target debris produced by EFP is analyzed. The results show that when the EFP’s impact velocity is 1650m/s and the target thickness is between 10mm and 70mm, the proportion of debris with quality less than 1g in the total fragment number decreases with the increase of the target thickness. When the thickness of the target plate is 40mm and the EFP’s impact velocity is between 1650m/s and 1860m/s, the impact velocity has limited influence on the fragment behind the target.

Some large-scale distribution network load data cleaning methods have the problem of excessive relative error. A load data cleaning method for large-scale distribution network based on improved random forest is designed. Based on the release characteristics of electrical loads, large-scale distribution network open source data is collected, and an anomaly data processing model is constructed based on improved random forests to describe the processing process of numerical error data, using the original sample set as a classifier and optimising the load data cleaning model. Test results: The mean relative errors of the large-scale distribution network load data cleaning method in this paper and the other two large-scale distribution network load data cleaning methods are 3.618%, 5.162% and 5.007% respectively, indicating that the performance of the designed large-scale distribution network load data cleaning method is better after incorporating the improved random forest algorithm.

Photovoltaic power generation system can not participate in the friendly interaction of power grid because of the lack of inertia damping. Virtual synchronous Generator（VSG） technology is an effective means to solve this problem. However, moment of inertia of technology based on virtual synchronous machine set is too large or too small are not conducive to the stability of the system frequency, based on the analysis of virtual synchronous machine running mechanism, this paper proposed virtual synchronous machine inertia adaptive control strategy, according to the load disturbance caused by frequency variation, the real-time dynamic adjust the moment of inertia, and thereby avoid frequency rapidly rising and falling. Finally, the effectiveness of the theoretical analysis is verified by MATLAB/Simulink simulation.

New housing was developed for a new cam lobe motor. Typical applications of full and reduced displacement load cases were applied and verified to avoid potential strength and fatigue risks. Both FEA simulation and durability test results show high fatigue risk at bolts between the front and rear housing. Furthermore, the housing structure was optimized to fix the fatigue risk and fit the casting process requirements. Finally, the optimized housing passed the durability test.

Assembly simulation technology occupies an important position in today's manufacturing industry, and its core is surface matching. In this paper, based on the traditional iterative nearest point algorithm, the algorithm was improved and optimized by combining the normal distribution transformation algorithm and adding constraints. And the algorithm can be divided into two steps: coarse alignment and static alignment. Finally, the algorithm was verified by experiments. It was shown that the algorithm was accurate and effective, while it had good computational accuracy. And an idea for the application of surface matching to practical engineering can be provided.

The baseline load assessment of users is an important prerequisite for compensating users. With the rapid growth of distributed power sources represented by distributed photovoltaic, its fluctuating load and photovoltaic power bring new challenges to accurate baseline load calculation. The fluctuating load and photovoltaic power of distributed photovoltaic users bring new challenges to accurate baseline load calculation. Based on this, the traditional baseline load calculation method is introduced firstly. Secondly, the baseline load calculation method of distributed photovoltaic users is proposed, including actual load estimation based on clustering, distributed photovoltaic estimation based on segment estimation, and the final baseline load calculation and effect evaluation. Finally, an example analysis shows that the accuracy of the baseline load calculation method proposed for distributed photovoltaic users is improved compared with the traditional common methods.

Escalator is an important transportation method in daily life. Handwheel is an elevator safety device which is used to move the car to the appropriate position and rescue the passengers. However, the turning force of some elevators exceeds standard. This article researches a new structure of handwheel. The turning handwheel has an auxiliary driving part, which can realize the traction operation of one machine by two people at the same time. The main driving part and the auxiliary driving part is connected by a fixing sleeve and a jacking screw. The torque is transmitted through a linkage shaft. The main drive part can also be used as an existing ordinary handwheel when the auxiliary driving part is removed. This handwheel can reduce the labor intensity of the operator and improve the operation efficiency and safety factor.

With the continuous development of manufacturing technology, ultra-precision machining, precision instruments, semiconductor manufacturing and biomedical engineering, precision positioning technology based on piezoelectric ceramics has been widely used in industrial production, weaponry and scientific research. It is one of the most important technologies to support the development of equipment to high precision, high efficiency and intelligence. However, the precision positioning system is difficult to meet the requirements of large stroke and high precision. Aiming at this problem, a large stroke piezoelectric linear motion platform based on piezoelectric drive is developed. In order to detect the source of error, a high-frequency response and non-contact yaw error detection system combining flat ruler and capacitive micro-displacement sensor is designed, and an error detection method is established. At the same time, in order to compensate the error, a micro-motion error compensation platform based on piezoelectric ceramic drive, elliptical amplification mechanism and flexible dumpling chain drive is designed, and experimental research is carried out. The results show that the proposed method in this paper can compensate the system error, and has good dynamic characteristics, which meets the positioning accuracy required by precision equipment.

In terms of dynamic analysis of metal V-belt CVT, under the objective conditions of less research theory and results, I studied its modal characteristics. Taking a domestic CVT as the research object, the three-dimensional modeling of metal sheet, the key component of CVT transmission mechanism, is carried out. Choosing magnesium alloy material can greatly reduce its centrifugal force. The three-dimensional model of metal sheet is established by SolidWorks software and imported into Ansys finite element software for modal analysis. Under different speed ratio conditions, the modal characteristics of the magnesium alloy metal sheet are analyzed, and it is concluded that the prestress has little effect on the natural frequency of the metal sheet.

A method based on the theory of gearing and the gear generation mechanism is proposed to analyze the influence of geometric errors of a linear axis on the position and orientation of instantaneous contact line. The mapping relation, utilized to describe the gear profile and the grinding disk profile is established between intrinsic parameters of a grinding machine and meshing parameters. Firstly, instantaneous contact line equation and error transformation matrix are built. Then six component geometric errors of a linear axis are introduced. Finally, a comparison is conducted between the theoretical contact line and the actual contact line to identify the influence of each geometric error. The application of the simulation illustrates that: the instantaneous contact line calculating method can accurately obtain the influence values of each geometric error, which provides a scientific basis for gear profile accuracy improvement in a large-scale gear forming grinding method.

In order to solve the problem of safety construction in power grid, the safety risk points of personnel/equipment/environment in typical operation sites are put forward, and the safety risks are classified and a risk feature database is formed. Establish risk protection requirements according to the types and impacts of different risks; This paper analyzes the security risks of the access layer, network layer, platform layer and application layer respectively, combs the security resources of each layer, introduces the hierarchical structure of the Internet power of Things.Aiming at the problem of power grid information security risk assessment, a niche optimization based on gene expression algorithm is proposed to improve the dynamic model. The algorithm first uses rough set theory to reduce the sample data by solving the best of the discrimination function, and then uses the niche model to improve the diversity of sample reduction and accelerate the speed of GEP algorithm. Finally, the genetic algorithm is used to realize the global search, and the comprehensive evaluation of the security level is obtained. It aims to promote the safety and health of Internet of Things in the power system.

The continuous access of renewable energy and distributed generation threatens the frequency security of microgrid. The frequency regulation capability of microgrid is greatly reduced. To improve the frequency stability of the microgrid based on energy storage, it is very important to adopt an appropriate frequency regulation method, which needs further research. Firstly, the principle of the virtual synchronous generator (VSG) is described, and the virtual power frequency and the virtual excitation controller are introduced. Thereafter, in order to improve the shortcomings of the traditional droop control, the frequency response is introduced to improve the droop control. Finally, the frequency regulation methods based on VSG, droop control, and improved droop control are simulated and compared. The results show that the frequency response link effectively improves the system stability. Among the three frequency regulation methods, the VSG performs the best frequency regulation speed as well as stability.

Power system is susceptible to kinds of abnormal behavior of electricity consumption. Detection of electricity theft can improve the stability of power system. Aiming at the problems of dependence on label data and low accuracy of existing electricity theft detection methods, this paper proposes a theft detection algorithm based on contrastive learning and clustering combination discrimination. The algorithm is composed of representation extraction module and clustering combination discrimination module. The representation extraction module firstly uses BiGRU to extract the context information of energy consumption data, and then obtains the representation of power data based on dilated convolutional network, and uses hierarchical contrastive learning to improve the learning effect of the network. The cluster combination discrimination module is based on K-means and adaptive DBSCAN algorithm, and uses a combination discrimination mechanism to classify the representations and determine theft. In this paper, the effectiveness of the proposed method is verified by the public dataset SGCC, and the experimental results show that the proposed method is superior to other unsupervised anomaly detection methods.

In order to realize accurate single-phase fault line selection of a distribution network with multiple cables and overhead lines, a method of single-phase fault line selection of distribution network based on knowledge atlas is proposed. On the basis of building the overall knowledge map model, collect and preprocess the distribution network line data, extract the characteristics of the line data using the convolution neural network method, and realize the single-phase fault line selection of the distribution network on the basis of fault detection and recognition. The simulation results show that the proposed method can accurately identify and locate single-phase ground fault, and provide a reference for ensuring the stable operation of distribution network.

The interaction between AC and DC in the power grid system and the characteristics of DC system will have an impact on converter transformer. The DC current enters the winding through the neutral point of the converter transformer, which changes the operating characteristics of the iron core, produces bias flux, and even affects the correct operation of relay protection. In this paper, a multi-channel feature fusion model is introduced, which has a good direction. The characteristic relationship between the fault impedance and the impedance components is obtained by measuring the impedance. The fault impedance is solved by using adaptive coefficients to effectively reduce the influence of fault resistance. Considering that the fault impedance angles of multi-channel protection of different line types are different due to different fault points, the influence caused by different impedance angles is effectively solved by adjusting the conversion between the measured impedance and the fault impedance. In the experiment, by comparing the relationship between the sensitivity of this scheme and the line impedance, the feasibility of the setting is analyzed. The research effect of this paper is proven. It is of great practical significance to study the relay protection of the distribution network.

This paper presents flyback converters with multiple outputs, which provide filament and modulator power supply for Traveling Wave Tube （TWT）. High-voltage isolation and multiple power outputs are achieved with magnetic integration. The high-voltage isolation multi-output flyback transformer was accurately simulated by Magnetic Component Tool of SABER, with the AC impedance, parasitic parameters, hysteresis loss of the winding analyzed. The accuracy of the design was verified by circuit model simulation and prototype testing.

According to the environmental control requirements of the metro station, the monitoring system of the metro electromechanical equipment automatically adjusts the cold water flow at the end of the central air conditioner or controls the starting equipment according to the environmental parameters of the station to meet the thermal load requirements of the station, under the premise of ensuring the basic ventilation and air conditioning of the metro station, to realize the green operation control of the metro air conditioner. In today's energy-saving era, the economic operation of the central air conditioning is crucial, and the energy-saving control demand of the equipment monitoring system is increasingly important. The energy-saving control of the metro environmental control system is the key topic of the system. This study focuses on the design of metro station electromechanical equipment monitoring system, and introduces the metro electromechanical equipment monitoring system composed of programmable controller as the main controller. The control system is advanced in technology. It uses communication interface instead of traditional electrical interface, and uses redundant dual-loop network to build system network, which greatly improves the reliability of the system. It has advanced domestic level and good economic and social benefits.

This paper introduces the research of fault diagnosis based on convolution neural network. Firstly, the electronic control lock, sensor and microcomputer are briefly introduced, then the problems and failure mechanism in traditional language signal processing are analyzed, and a new method, "Post Signal to Noise Ratio Method" (NOPNL), is proposed; BP algorithm is used to train the stiffness function and expected threshold, and a probability adaptive factor weight vector model is established to predict the noise control of electromechanical actuator under sliding mode variable structure. Finally, the comparative experiment of test results shows that this method has certain advantages and feasibility in practical application.

With the continuous development of the new generation of semiconductor devices and modules, the size of high-end chips has also been further reduced. With the purpose of adapt to the rapid development of high-end chips, the chip mounting technology and equipment have also entered a rapid iterative development stage. Nowadays, the chip mounter is developing towards the direction of high intelligence, high precision, high efficiency, green and automatic. High precision patch equipment has been the focus of research at home and abroad. This paper summarizes the current situation of the demand for high-precision mounting technology of optical module laser in the 5G/6G field, introduces the main performance index requirements of high-precision mounting machine equipment, and systematically expounds the application status, advantages and disadvantages of high-precision mounting machine from three aspects of visual detection technology, mounting path optimization, and motion control system. The research shows that how to improve the speed and precision of mounting is still the bottleneck of the industry. Therefore, the research on the key technology of high precision and high-speed mounting has become an important competitive focus in the field of chip mounter equipment.

The concept of smart home has been proposed for 30-40 years, but so far, many standards and technical support are still in the laboratory research stage, and people usually only hear its sound but not its shape. With the development of IoT technology, micro devices that can achieve specific functions are gradually integrated with our traditional household facilities to provide us with an intelligent and efficient, comfortable, and safe living environment. In order to meet the social concept of energy saving and environmental protection, the electric power department usually monitors the electricity consumption of households in a certain area in real time and implements staggered power supply during peak periods when electricity is tight,or implements limited power supply for households that use electricity too wastefully. The new research approach used in this paper combines the study of computers and green energy. On top of the computer big data combined with the results of big data research combines the research in this field and computer big data model, which makes a certain pavement for our future funny research.

The level and theodolite are used in the calibrator of the current automobile headlamp tester to align the optical axis center, this method needs many people to cooperate with the operation, the low degree of automation is insufficient. To solve the problem, this paper presents an automatic alignment device and method for calibrator optical axis of vehicle headlamp tester, introduces the structure, composition and principle of the alignment device and the specific implementation methods and steps. The comparison of experimental data shows that the alignment device has the advantages of high automation, simple operation and high accuracy. It can replace the existing level and theodolite to ensure the alignment of the luminous optical axis center of calibrators for headlamp tester of motor vehicle and the geometric center of the illuminometer probe.

A zonal fault location model based on the improved binary dragonfly algorithm is proposed to solve the problem of fast and fault-tolerant fault location in multi-branch distribution networks containing distributed power sources. Firstly, a chaotic mapping strategy is introduced in the initialization stage of the algorithm population to improve the initial population's quality. The linear inertia weights of the original dragonfly algorithm are nonlinearly enhanced to improve the convergence speed of the algorithm. The equivalent partitioning model of distribution networks with distributed power sources is established based on the "black box method," and a location correction mechanism is added to guarantee location accuracy. Finally, the simulation is verified in a multi-branch distribution network with distributed power supply. Compared with the traditional binary dragonfly algorithm partitioning model, the number of iterations of localization is reduced. In addition, the improved binary dragonfly partitioning model can quickly and accurately locate the fault section for different fault locations and aberration points.

It would be possible to tune a dual-band terahertz absorber that has the polarization property and angle-insensitive is lifted in this paper, which is a typical sandwich structure consisting of a graphene structure with a chirped wheel sitting on top of the top layer, an insulating medium placed in the middle and a bottom layer gold ground plane. Simulation results show that there are two absorption peaks at 1.69THz and 4.49THz, with absorptivity of 98.73% and 99.68%, respectively. At resonant frequencies, these two absorption peaks could be varied dynamically by rescaling the graphene's chemical potential,thereby providing a novel method for developing actively tuned terahertz absorbers.

In order to solve the problem of cab tremor caused by the crawler crane rotary structure in quick start and quick braking. Therefore, multi-software co-simulation technology is adopted. Through Amesim and Adams software, the electromechanical and hydraulic joint simulation model of the rotary structure of the crawler crane was established to co-simulate the slewing mechanism of the crawler crane. By optimizing the hydraulic system model, the problem of hydraulic motor oil inlet pressure during fast start and hydraulic motor return pressure during fast braking is solved by optimizing the hydraulic system model, resulting in cab tremor.

In order to effectively maintain and operate the smart substations, a data mining and analysing method for defects of secondary equipment based on the FP-Growth algorithm is proposed．The basic ideas of association rules and FP-Growth algorithm are introduced firstly, then the defect model and the system framework are proposed to mine and analyze the defect data. Through the analysis of the actual defect data of a substation using the proposed method, it shows that the proposed method can effectively find the relationship among secondary devices, manufactories, defect properties, defect causes and other factors. By data mining, it can provide valuable information for efficient maintaining and operation of the substations. Some auxiliary suggestions are given for operation of secondary device finally．

Influenced by the complex environment on the AC/DC hybrid power system, converter transformer is susceptible to inrush current or DC bias interference, resulting in false blocking of differential protection during internal fault. In order to distinguish inrush current and internal fault accurately, this paper proposes an inrush current identification scheme for converter transformers based on the flux-current characteristic model matching method. Firstly, the magnetization curve model is selected to fit the nonlinear magnetization characteristics of the transformer, and a model matching scheme based on voltage comparison is designed. Then the model matching degree index (referred to as matching per unit value M in this paper) is constructed to quantitatively describe the model matching degree, and the inrush current identification criterion based on the model matching degree M is proposed. Finally, the action reliability of the proposed identification criterion is verified by simulation experiments.

Abstract: This study mainly analyzes the influencing factors of four-wheel independent drive/independent steering in the process of vehicle operation, and establishes a two-degree-of-freedom dynamic model under the ideal condition. By changing the dynamic model of carsim, Realize the carsim model of four-wheel drive and MATLAB/simulink joint dynamic simulation, the output analysis results, for more accurate and more adaptable to the complex environment of the control to lay a theoretical analysis foundation, for the consideration of working conditions, four-wheel independent drive/independent steering vehicle in the process of motion stability is very important, through the ideal sliding mode control, Improve the handling stability of the car.

In order to resolve the problem of vibration and noise caused by the crank and slider mechanism of the fascia gun during high-speed operation, the substance-field model in the theory of inventive problem solving (TRIZ) was used to decompose the function of the crank and slider mechanism. Innovative ideas were proposed in combination with 76 standard solutions to identify the objects that needed to be optimized and improved. Then, applying the relevant theory of classical mechanics, the specific parameters that needed to be improved for the optimization of the object were obtained by the analytical method. Then, the multi-body dynamics analysis software Adams was used to build a virtual digital prototype model. In order to minimize the disturbance force on the rotating pair connected to the motor shaft and the crank, the multi-parameter optimization design was carried out, and the optimal design scheme was solved. Finally, the physical prototype based on the optimization scheme was tested. The test results showed that the vibration acceleration of the prototype in the reciprocating direction of the massage head was reduced by 76%, and the noise level of the whole machine was reduced by 55%.

In order to improve the accuracy and speed of simulation, a piecewise linear (PWL) network simulation method based on FPGA is proposed. Through RT-LAB hardware in the loop simulation platform and supporting FPGA development tools, a simulation system based on FPGA is established. The nonlinear element is modeled by PWL approximation method. The system matrix method that accurately supports the characteristics of any PWL element is applied, so that the realtime simulation system can fit the real operating state of the system, and has very good simulation accuracy and simulation results. In order to verify the effectiveness of the system, an energy storage grid connected test system is established by using the PWL network system based on FPGA. The experiment proves the effectiveness of the PWL network simulation based on FPGA.

The article focuses on the basic concept and theoretical basis of EMD, and analyzes the advantageous aspects and shortcomings of EMD. It also introduces various methods to improve EMD, such as the proposed EEMD method, which describes the theory and advantages of EEMD, the EEMD-CNN method, which is to eliminate the added Gaussian white noise first, before the decomposition of EEMD to improve its accuracy, the CEEMD processing, which adds two opposite Gaussian white noises, and the MEEMD processing, in which the CEEMD processing adds the concept of cliff value to improve its decomposition efficiency and make it more practical.

Aiming at the problem of inaccurate hand positioning caused by the Kinect sensor placed too far away, we propose an advanced motion classification method. Combining Kinect with sEMG to classify human upper limb movements.Collect human body depth images and sEMG signals, extract human skeleton coordinate points to complete joint angle calculation. Perform data processing on sEMG signals to construct feature vector vector space.Then perform BP neural network training to classify 6 kinds of gestures. The experimental results show that the classification accuracy of arm gesture recognition is 98.5%, and the classification accuracy of hand gesture recognition is 97.6%. Therefore, our method has good recognizability for detailed motion and can meet the requirements of gesture motion recognition classification.

This paper analyses the variation of friction coefficient with the meshing position and then establishes a helical gear bending-torsion-shaft vibration model considering time-varying friction, tooth backlash, and other nonlinear factors. The nonlinear dynamic characteristics of the helical gear meshing process and the influence of variable friction on the meshing process are analysed. The results show that the time-varying friction force obviously aggravates the vibration in the lowspeed stage of the gear meshing process, and the friction force is the largest at the contact point near the tooth root and tooth tip.

With the development of robotics and the rapid diffusion of products, more and more specialized products are available for the agricultural sector. In order to achieve non-destructive picking of spherical fruits and vegetables, especially tomatoes which are soft and fragile. In this paper a series of research works are carried out on this topic. A multi-link picking mechanism is purposefully proposed which is composed in three dimensions and whose basic actions are performed by active cylinders in a collaborative sequence. By analyzing and solving the hand claw structure, the action statistics of the three fingers under different drives are simulated and the force values required for picking are determined. On the basis of establishing the ideal action to complete the picking, the sequence of control of the three jaw cylinders to complete the basic action is determined combined with simulation experiments to determine the ideal picking criteria in the implementation process. The design is verified by simulating the picking process to see how well it achieves the design objectives.

The deployable structure of the antenna proposes to adopt a PMSM (permanent magnet synchronous motor) to improve reliability. The traditional control method of PMSM requires mechanical sensors, which brings problems such as reduced reliability. The implementation of the high-frequency signal injection method is simple and flexible, and the method is not sensitive to motor parameters changes, so it has become the preferred method. In this paper, a sensorless control algorithm for the deployable structure of the antenna based on square-wave injection method is studied, which does not use filters compared with the sensorless control algorithm based on pulsating injection method, thereby improving the bandwidth and dynamic performance of the system.

With the intensification of globalization, the requirements for port container throughput are getting higher and higher, and automated AGVs have emerged. Among them, a reasonable path planning of AGVs is very important. Aiming at the path planning and conflict avoidance of AGVs, based on the improved A* algorithm, this paper proposes an AGV steering cost estimation function and a multi-AGV occupancy program, then gives an AGVs path planning strategy. Compared with the traditional AGVs operation mode, it improves working efficiency and reduces the amount of calculation, which has certain significance for the low-cost upgrading of traditional terminals. At the same time, the method is more universal and provides a reference for related research and industrial applications.

The purpose of this paper is to design an intelligent wheelchair that can follow the patient's walk independently. Besides, it can help rehabilitation patients recover better through the intelligent automatic control system. On the one hand, the cost compensation function is introduced to improve the traditional Astar algorithm. It can make the intelligent wheelchair more adaptable to the environment. The underground environment is simulated to verify it. Simulation shows that the surface intelligent wheelchair can identify the path more accurately. On the other hand, the wheels of the intelligent wheelchair and the driving motor of the mechanical arm both use IPMSM. To control the motor more efficiently and accurately, the MTPA control method is adopted in this paper. The process of an intelligent wheelchair starting, moving at a constant speed, and slowing down and stopping on flat ground is simulated and verified. The simulation shows that the intelligent wheelchair can realize the start and stop acceleration which makes the patient feel comfortable. The results show that the intelligent wheelchair has a good effect on the recovery of patients.

As a new type of flow meter without movable parts, ultrasonic water meter has the advantages of high sensitivity, large measurement range, high repeatability and small start flow. It has been applied to the main pipe network of urban water supply system. However, the ultrasonic water meter using for domestic area has the problems in small pipeline due to the short acoustic path. In order to solve the above problems, the two type’s ultrasonic water meters with U-shaped acoustic path are designed. The CFD fluid simulation technology is used to simulate the two pipelines. The velocity map of the horizontal section and the vertical section are extracted respectively. The relationship of flow rate and flow correction coefficient is analyzed at the direction of flow and pipe section. The flow rate variety is also analyzed. The simulation results show that the brace pipeline has more stable flow field area and better symmetry. The final experimental results show that the characteristics of the brace pipeline are better than the column pipeline.

In order to improve the accuracy and timeliness of the detection results, a design method of online virtual fault injection based full-life cycle reliability detection model for relay protection devices is proposed. The failure rate function and reliability function of the relay protection device are calculated. According to the calculation results, the basic properties of the relay protection device and the operation characteristics of the relay protection system are analyzed. The reliability parameters of the relay protection device are estimated using the three-parameter Weibull distribution model. The reliability of the relay protection device is tested. After the fault injection is randomly simulated, the reliability is studied. The MARKOV algorithm is used to calculate the reliability state parameters of the relay protection device. Based on the reliability state parameters obtained, the reliability detection matrix is established to complete the reliability detection of the large relay protection device. The experimental results show that the difference between the detection results of this method and the actual results is small, and the real-time detection is strong, which verifies the application value of this method.

To address the issues of low degree of visualization, untimely data interaction, and difficulty in cyber-physical fusion of the fidget spinner manufacturing line, this paper builds the digital twin architecture for the fidget spinner manufacturing line and develops a "geometry-physics-behavior-information control" four-dimensional fusion modeling method, which adds the information control dimension to digital twin modeling. This method maps the geometric features and physical characteristics and reveals the behavioral mechanisms, control logic, and virtual-real mapping rules between the physical entity and the digital twin model. Through an information service system that is established and implemented, the proposed technique is finally verified as effective, and recommendations for the digital transformation of small and medium-sized manufacturing firms are provided.

To solve the problems of complex control structure, too many parameters to be tuned and complicated modulation module design in the traditional dual closed-loop control strategy of neutral point clamped (NPC) three-level PV inverter. A control strategy is proposed for NPC three-level PV inverters based on multi-step-ahead finite control set model predictive control (FCS-MPC). Based on the derivation of the mathematical model of the PV inverter, the current predictive control of the PV inverter in the αβ frame is realized based on the basic principle of FCS-MPC, which effectively reduces the control parameters of the PV inverter. Additionally, based on the inherent advantages of FCS-MPC, the mid-point potential balance of the DC side, reducing switching frequency and harmonic are simultaneously realized by setting the appropriate objective function. Furthermore, the accuracy of the prediction is further improved by the use of multi-step-ahead predictive control. For the harmonics problem during the fault ride-through of the conventional PV inverter, the causes of harmonic generation are revealed and a notch filter is designed to reduce the harmonics generated by the PV inverter during the low voltage ride through (LVRT). Finally, the time domain simulation software is used to verify the effectiveness and feasibility of the control strategy in this paper.

Active suspension as an advanced vehicle vibration damping device has important application value, but the current research on the control strategy of the active suspension is mostly based on simulation mode, lacking experimental research. This paper presents a hardware-in-the-loop test research on the 1/4 vehicle active suspension test platform based on hardware-in-the-loop simulation techniques. Active suspension Simulink models of a linear quadratic regulator control strategy and an active suspension based on a modified reference skyhook model sliding mode control strategy are developed. Simulations are carried out under different road excitations (sinusoidal and bump) and the suspension performance evaluation parameters are determined so that the control effect can be evaluated and analyzed. The software for the hardware-in-the-loop test is the QUARC and the hardware consists of a computer, 1/4 vehicle active suspension test platform, data acquisition card and power amplifier. Compared to the linear quadratic regulator (LQR) controlled active suspension, the sliding mode controlled (SMC) active suspension based on the reference skyhook model provides more significant improvements in the suspension performance indicators of sprung mass acceleration, suspension dynamic travel and tire dynamic load. The 1/4 vehicle active suspension hardware-in-the-loop test provides a basis for theory and broadens the research path for non-real vehicle validation.

The tilt of the leveling ship in the leveling process has to meet the high precision process requirements while at the same time minimizing the actuator action frequency in the control process and extending the actuator life, which is very important for leveling processes with time delays and complex external disturbances. A group of advanced control strategies must be designed to match them. Firstly, a ballast leveling mechanism model is established based on the hydrostatic characteristics of the ship, followed by the design of a multi-switch device predictive control algorithm. By making the rolling time domain larger than the maximum time delay and ensuring that the switchgear combination is constant in the time domain, LESO is introduced for online prediction of unpredictable disturbances and rolling optimized predictive control of the equipment combination, the influence of time delay and external disturbances on the control system is weakened, and the switching frequency of switchgear is reduced. In the final simulation, the tilt tracking RMSE was reduced by 22.2% compared to conventional switching control, and the number of actuator switches was reduced by 6%.

The vehicle stability control system is an onboard computer that calculates the instantaneous dynamics and potential future movement trend of the vehicle through a series of algorithms and makes the vehicle in a relatively safe driving range through the control of vehicle components. Its main purpose is to assist the driver and play an effective role when the vehicle movement is in danger or the driver cannot effectively control the vehicle. This paper summarizes the concept and application of vehicle stability control, introduces the research status of vehicle stability control systems, summarizes its current research, and provides some references for related research.

Photovoltaic, energy storage and charging pile integrated charging station is a high-tech green charging mode that realizes coordinated support of photovoltaic, energy storage and intelligent charging. In this paper, a control model of each part of comprehensive charging station considering the benefits of users and charging stations is established. A heuristic algorithm is used to solve the benefits under the cooperative control strategy of comprehensive charging station, and a new collaborative control method is proposed. In addition, income sensitivity and other indicators are designed to quantitatively analyze the relationship between the total revenue, quantity and subsidies of electric vehicles under the coordinated control strategy of integrated charging station. Can support the power company integrated charging station project.

The low inertia power systems with high proportional power electronic inverters cannot provide sufficient inertia to maintain system balance. The inverters based on virtual synchronous generators (VSG) can provide virtual inertia to the grid. However, when the damping effect is not significant, the rotor motion characteristics brought about by the VSG may cause low frequency power oscillations. To solve this problem, a low-frequency oscillation suppression method (AI-VSG) for low-inertia power systems based on auxiliary inertia is proposed in this paper. Firstly, a power frequency control model of the grid-connected inverter system is developed. Next, the response performance of VSG and AI-VSG is compared and theoretically verified. Finally, as shown in the Bode diagram, the proposed method significantly attenuates power oscillations and improves the inertial response, even in the presence of poor system damping. The simulation results validate the effectiveness of the proposed oscillation suppression method.

If the drill bit breaks in the process of machining the spinneret with large length diameter and small pilot hole, there will be the problem that the original plate is discarded, the new plate is replaced,The problem of wasting resources. According to the signals of the axial force and torque generated by the drill bit, a monitoring system for the drilling tool of the spinneret micro-guide hole was developed on the Lab VIEW platform for the first time, which can realize real-time monitoring of the drilling process. The micro-hole drilling experiment proves that the break of the drill bit is more obviously affected by the torque increase.value *10 to monitoring domain is determined by the reliability function of the tool axial force and torque value of 5 reliability R value near 0.5, the bit number is less than the critical value of failure theory, system prediction tool withdrawal, pilot hole drilling process can avoid drill fracture,The number of drill holes of the spinneret guide holes is increased, thereby reducing the processing cost and effectively improving the productivity.

The new energy needs to be sent out by high-voltage transmission system, and the grid-connected criteria of wind power require that the fan must have the low-voltage ride-through ability. According to the structure of permanent magnet synchronous generator and converter, the control strategy is analyzed, and a comprehensive LVRT control strategy based on power compensation and unbalanced power consumption of unloading circuit is proposed. On this basis, the influence of the proposed LVRT strategy on the transient voltage is studied. According to the influence factors of transient voltage, the suppression measures are given. Finally, a simulation model is built in Matlab/Simulink to verify the effectiveness of the proposed LVRT control strategy and transient voltage suppression strategy.

The current assembly line generally adopts an automatic assembly line with a fixed layout and a number of fixed stations which cannot fixed the requirements of flexible, multi-variety, small-batch cabinets assembly operation. Therefore, in this paper we present a modular overall design assembly line. It is divided into upper and lower parts modules, transmission modules, steering modules, and assembly modules, that can meet the limited space category and can be high flexibility.

With the development of high-speed RF circuits and high-voltage switches, the enhancement-mode (E-mode) GaN-based high electron mobility transistors (HEMTs) have become a hot topic in those fields. In this work, to improve the device performance of E-mode HEMT, p-GaN gate combined with recessed-gate was proposed. Moreover, the influence of structure parameters such as Al component and thickness of AlGaN barrier layer and the depth of recessed gate on device performance were investigated systematically by theoretical simulation. The results show that the saturation current increases and threshold voltage decreases with the increasing of Al component and thickness of AlGaN barrier layer. In addition, the saturation current decreases and threshold voltage increases with the increasing of the recessed gate depth. So, to obtain relative larger threshold voltage and saturation current, the Al component and thickness of the AlGaN barrier layer and the recessed gate depth for the p-GaN gate HEMT combined with recessed-gate structure should be moderate.

It is important to study the water surface infrared characteristics caused by the hot wake of the underwater vehicle from the perspective of infrared radiation for submarine detection. At present, most of the experimental water environments on surface infrared characteristics are set up as uniform environments or ideal linear temperature stratified environments. However, the temperature distribution environment of the real sea is complex and diverse, and further improvement of the water environment is still needed to obtain more realistic results. Therefore, this paper constructs a nonlinear temperature stratified environment that conforms to the real water environment, and conducts numerical simulations and experimental validation in this environment to observe the infrared characteristics of the water surface. The results show that in the nonlinear temperature stratified environment, the submarine will produce cold wake phenomenon. Compared with the uniform temperature environment in the same working condition, the wake is longer and less likely to dissipate, and the surface infrared characteristics can be detected more obviously in the non-linear.

The ROPS (Rollover Protection Structure ) test bench is a mechanism used to detect the vehicle ROPS. For the consideration of loading capacity and loading speed, the hydrostatic loading method is widely used at present. In the specific test process, due to the strong nonlinearity of the hydraulic cylinder and the unknown load disturbance caused by the unpredictability of the loading structure, the stability of the control system of the test bench will be reduced, and due to the detection of the protection ability of the three directions of ROPS, there is still a problem of long loading time in the experiment. Aiming at this problem, a fuzzy active disturbance rejection position control system combining fuzzy control algorithm and active disturbance rejection control algorithm is proposed. Firstly, the composition and principle of fuzzy active disturbance rejection position control system are introduced. The mathematical model of the system is established. The position control strategy and specific control method of the static pressure test bench are proposed, and an active disturbance rejection controller is designed. Then the electro-hydraulic co-simulation model is established to study the position control performance and system stability of the ADRC. Finally, the effectiveness of the fuzzy active disturbance rejection control algorithm is verified by real machine test. The results show that the fuzzy active disturbance rejection controller has higher stability and shorter detection time than the fuzzy PID controller.

As a new additive manufacturing technology, electrostatic printing has the advantages of high resolution, high material applicability and no clogging. The electric field distribution (EFD) has a significant impact on the jet stability and the deposition quality during electrostatic printing microstructures. The distribution characteristics of electric fields were investigated using the finite element analysis software COMSOL Multiphysics in this paper. The distribution patterns of the electric field strength in the printing space were studied. The results show that the EFD in the three-dimension space within 0.5 mm from the nozzle is extremely complex, and jet instability occurs in this region. The influence of micropillar on the changing patterns of EFD was investigated and the self-alignment effect in electrostatic printing was revealed. This result provides an effective analytical tool for electrostatic printing, which is important for improving the regulation level of electrostatic spraying for realizing the controlled microstructures of electrostatic printing.

In order to solve the problems of nonlinear unknown term and external environmental disturbances of the under-actuated ship motion system, an indirect control method based on adaptive global fast terminal sliding mode control (GFTSMC) algorithm is devised for path following of under-actuated ships. The path following controller consists of course guidance law and heading controller. An iterative sliding mode scheme based on nonlinear hyperbolic tangent function is introduced to design the course guidance law in order to restrict the maximum yaw rate. Then the ship's heading is controlled by heading controller, the GFTSMC algorithm is introduced to nonlinear state error feedback (NLSEF) in order to reduce the chattering. The nonlinear unknown term is estimated by radial basis function (RBF) neural network to improve the robustness and the adaptive ability of the controller. The simulation results show that the ship can follow the desired path precisely under the external environmental disturbances such as wave, wind and current, proving the effectiveness of the designed algorithm.

In order to reduce the number of gates in quantum circuit to reduce the error rate running on NISQ device, it is demonstrated that the template satisfies the relevant conditions for mapping to the linear topology structure in the quantum system, and a quantum circuit connectivity constraint mapping optimization method based on template matching is proposed. This method reconstructs the templates by adding SWAP gates or replacing bridge gates to make them meet the connectivity constraints of linear topology. Aiming at the linear subcircuits in quantum circuits that satisfy the connectivity constraints of quantum topological structure, the template matching optimization method is used to replace the gates in the circuit that match the template with a few remaining unmatched gates in the template. Finally, the optimized circuit also satisfies the connectivity constraint of quantum topology. Using a set of NISQ benchmark circuits, compared with the t|ket⟩ compiler, the test results show that the number of CNOT gates can be further reduced by an average of 28.71 %, up to 40 %.

LS-DYNA was used to simulate and analyse the safety of spent fuel assembly dropping during hoisting. Most of the previous studies focus on the stress and strain level of storage rack, but lack of analysis of the assembly. In this paper, a near-ground model with 1/4 of the assembly including all the features is established based on considering the computational efficiency and accuracy. Then, based on bilinear elastic-plastic material constitutive and explicit dynamic algorithm, the deep drop condition of the assembly was analysed. It was found that the bottom of the guide tube and the edge of the storage cavity were the most dangerous. The structural integrity of the assembly and storage rack were evaluated by strain and deformation failure method, and the results showed that they met the safety requirements. The simulation method and conclusion of this paper can provide reference value for the safe hoisting of spent fuel assembly and storage rack.

Gear is an important part of power transmission between machines. Long Term and short term memory network (LSTM) is adopted as the basic model for gear fault detection. Aiming at the problem that the model hyperparameters of LSTM are difficult to be determined manually, by using the improved particle swarm optimization (IPSO) to find the optimal LSTM superparameters automatically. Optimize the learning factor and inertia weight in PSO to enhance particle optimization ability, so as to build IPSO-LSTM model with better detection ability. In this paper, the gear fault data set published by the University of Connecticut was used to verify the detection model, and the fault detection accuracy of the gear fault data set reached 98.7%. Compared with the unimproved PSO-LSTM model, LSTM and CNN, the accuracy rate is increased by 2.9%,7.4% and 10% respectively.

Under the "double carbon" goal, the proportion of new energy in China's power system is increasing year by year, and the power grid is facing huge challenges under the "double high" power system. Photovoltaic power generation has a strong volatility. After grid connection, it has no ability to provide support for the frequency stability of the system. On the contrary, it will bring uncontrollable interference to the grid. Especially when the power grid has serious frequency fluctuations, the ability and time of frequency control are more difficult to meet the system requirements. The above problems are huge challenges for PV grid connection. The energy storage has the characteristics of fast response, high climbing speed and accurate action. In order to improve the impact of photovoltaic grid connection on the system frequency, introducing energy storage to assist the primary frequency modulation of photovoltaic stations can enhance the friendliness of photovoltaic power generation. Finally, this paper studies the primary frequency modulation control strategy of photovoltaic station assisted by energy storage. Through simulation, the curves of energy storage in different situations and the amount of action are obtained.

In the research of target motion analysis, the target motion is usually approximated as a uniform linear target in most cases. However, in the actual environment, the target motion is usually a non-uniform linear motion and the target motion trajectory is mostly a curve, so it is particularly important to estimate the target state under this motion situation. In this paper, the motion analysis of low-speed and slow-turning targets is studied. Interested in low-speed and slow-maneuvering moving targets less than 6 knots, the deviation compensation algorithm of pseudo-linear Kalman filter in two-dimensional space and three-dimensional space is derived. Finally, the performance of the algorithm is verified by simulation, and the influence of measurement error and initial distance on the performance of the algorithm is studied.

The research shows that the development trend of power factor correction (PFC) circuit is to continuously improve its conversion efficiency to meet higher requirements. In this paper, a totem pole bridgeless PFC rectifier with a power of 6.6 KW is designed. The diode in the traditional totem pole topology is changed to a low frequency switch tube. A composite control algorithm combining repetitive control algorithm with proportional integral (PI) control algorithm is proposed, which improves the steady-state characteristics of PI control, reduces the harmonic distortion of input current, and improves the input power factor. In order to test the effectiveness of the control strategy, the Simulink tool of MATLAB software is used to simulate the main circuit and control circuit model. FFT analysis of the simulated current waveform shows that the totem pole bridgeless PFC using the composite control can theoretically obtain good electrical performance.

The orderly control strategy adopted in the charging station can decrease the peak-valley difference (PVD) and promote the normality and safety of the charging station in the electrical power grid. However, the orderly control strategy will lead to inconvenience for EV’s owners to charge and limit its large-scale application. Therefore, it is an urgent problem to reasonably optimize the charging and discharging process of electric vehicles in the optical storage charging station. The research in this paper is mainly aimed at making the grid side meet expectations, and making the EV’s owners charge the lowest. In this paper, aiming at the minimum PVD of the grid and the lowest EV’s owners charging cost, taking into account the maximum load and EV’s owners charging time of the charging station, the genetic algorithm is used to solve the problem, and the coordinated control model for optimizing the charging and discharging behavior of electric vehicles in the optical storage charging station is established. The feasibility of the strategy is verified by an example analysis. The method significantly reduces the PVD of the power grid.

After the reliability analysis and maintainability analysis of numerical control machine tools, the influence degree of key components is analyzed respectively under the premise that it is not repairable and repairable. Under the premise that it is not repairable, the probability influence degree analysis is carried out, and on this basis, the critical influence degree analysis is carried out. Under the condition of repairable, Natvig method is used to analyze the comprehensive influence degree. Finally, the analysis results of influence degree were compared and analyzed. The Sorting results of influence degree of key components are consistent with the reality, and obtained results can further guide the reliability design and reliability growth of CNC machine tools. The Natvig method applied in this paper provides an effective way to study the repairable influence degree of CNC machine tools.

Due to the advantages of cleanness, high efficiency and rapid start-up, gas turbines play an important role in peak shaving and frequency modulation in China's power supply. The primary frequency modulation capability of gas turbines is of great significance to the safe operation and frequency stability of the power grid. To handle the control challenges of gas turbine primary frequency modulation, such as loop coupling and large overshoot, a data-driven proportional-integral (PI) control strategy is proposed for the gas turbine primary frequency modulation system, and a reasonable parameter tuning method is provided. The stability of data-driven PI is discussed by analyzing the distributions of data-driven PI parameter in the stability region. Finally, the proposed method is applied to the primary frequency modulation control of a typical heavy-duty gas turbine unit. The simulation results show that the gas turbine unit with the proposed method can obtain the best control performance of the primary frequency modulation with good robustness. The proposed method also has good practical application potential.

Compared with alternating current(AC) power grid, flexible direct current(DC) power grid has obvious advantages such as good controllability, flexible operation mode, and multiple applications, which also makes it the preferred scheme for new energy grid connection. In order to ensure the reliability of flexible DC power grid, it is necessary to use high-voltage direct current(HVDC) circuit breaker for fault isolation, and it is urgent to develop and study the reliability evaluation method of HVDC circuit breaker. This paper gives the circuit topology of HVDC circuit breakers firstly, then analyzes the relationship between single component failure and overall failure in combination with component redundancy.On this basis, this paper proposes the stability evaluation index system of DC circuit breaker and establishes the stability evaluation model.

The current conventional power quality control method mainly realizes the control of power quality by designing the high voltage power control strategy for suppressing power routers, which leads to poor control effect due to ignoring the influence of harmonics. In this regard, the power quality control method of flexible AC transmission project based on harmonic suppression is proposed. The multi-objective voltage reactive harmonic optimization algorithm is designed, and the harmonic tidal wave voltage value is calculated, and the power quality control strategy is proposed. In the experiment, the control effect of the proposed method is verified. The experimental results show that when the proposed method is used for voltage control, the harmonic voltage distortion rate of the grid is low and has a more ideal power quality control performance.

The inertial/starlight combination is an effective autonomous navigation system at long distances and long endurance with good development prospects. In view of the limited test conditions and high cost, the software is integrated to generate dynamic navigation parameters of the inertial/star tracker combination system. According to the carrier dynamics equation, the trajectory generator generates the output information of gyroscope, accelerometer, inertial navigation and star tracker, which provides raw data and performance evaluation benchmark for the research of inertial navigation, star tracker navigation and inertial/star tracker navigation algorithm. The simulation under different parameters shows that the software is correct and effective.

The current Testability Physical Verification (TPV) is the most widely used, it is still limited by many factors, such as the obvious damage or even destructiveness of the fault injection; the problem fault caused by the physical packaging cannot be injected. Carrying out Testability Virtual Verification (TVV) can effectively solve the above problems. However, the development of TVV is insufficient, the technology is difficult, and there is a lack of practical engineering applications. Based on the digital twin technology, this paper establishes a testability-oriented digital twin model of the gear transmission system through the MATLAB/Simulink platform. The fault simulation can be injected into the twin model to simulate the operating state of different faults. After analysis, the fault signal is classified and identified , and the classified result can reach 84.85%. The results verify the feasibility of using the twin model for TVV.

VMD (Variational mode decomposition) is a commonly used method for processing rolling bearing fault signals. VMD enables efficient separation of intrinsic modal components and it can match the best center frequency and the appropriate bandwidth range for each mode. It should be noted that the number of modalities and penalty parameters need to be set before execution. We propose an optimization algorithm for VMD based on the Whale Optimization Algorithm (WOA) and then select an iterative formula for the iterative update. The formula is chosen in terms of the magnitude of the convergence factor to output the best VMD parameters. The effectiveness of this method is proved through the processing of the rolling bearing inner ring fault signal.

Aiming at the non-stationary and nonlinear characteristics of tool wear signal in cutting process and the problem that it is difficult to effectively identify the wear state, a tool wear state recognition method based on feature fusion and fuzzy neural network is proposed Multi-domain features were extracted from frequency domain and time-frequency domain, and then several features with higher tool wear information were selected according to pearson correlation coefficient. Then, the optimal feature set was obtained by feature fusion using PCA algorithm. Finally, the multi-dimensional optimal features are input into the fuzzy neural network for training, and the mode state model is established to identify the tool wear state. The experimental results show that the method can accurately identify the tool wear state, which verifies the superiority of the method.

The oil-water medium on the track and wheel surface will directly affect the adhesion characteristics of wheel-rail and the braking performance of the train.In order to ensure the safe and stable braking of the train, it is a need to research the wheel-rail adhesion in oil-water medium. Based on the partial elastohydrodynamic lubrication theory, a numerical wheel-rail rolling contact model in the medium of oil-water was established. The influences of creep speed, train speed, surface roughness, wheel diameter and axle load on adhesion coefficient were analyzed. Based on the POLACH model with measured data, a functional friction factor is designed, which takes into account both train speed and creep speed. An improved POLACH model for describing the adhesion characteristics in the medium of oil-water is obtained, and the exactitude of the improved model is tested and verified by comparing with the experimental data. The simulation outcomes show that the adhesion coefficient based on improved POLACH model is consistent with the experimental results and meets requirements of BS EN 15595-2018 for wheel-rail adhesion characteristics, it provides a theoretical basis and engineering guidance for train traction and braking control.

Piston rod is a typical slender shaft part. In order to improve machining quality, reverse turning is preferred according to production experience. In order to provide the theoretical basis for the reverse turning of the slender shaft and quantify the processing quality, the results show that the reverse turning of the slender shaft is about 5 %-10 % higher than that of the process parameters.

The recovery of ship-borne UAV is an indispensable and important part of the study of ship-born UAV. In the process of UAV recovery, it is not only necessary to overcome the control system error and environmental interference that ordinary aircraft face when landing, but also to overcome the influence of deck movement on the ideal collision point and the interference of the bow and tail airflow disturbance on the flight trajectory. This paper expounds the development status of shipboard fixed-wing unmanned aerial vehicles, summarizes the structure composition, recovery principle and technical characteristics of common unmanned aerial vehicle recovery devices at home and abroad, and introduces in detail the outboard net recovery technology in the research of unmanned aerial vehicle recovery technology important role.

Gear mesh stiffness is an important parameter in the study of gear dynamics, and it is of great significance to accurately calculate gear mesh stiffness. The numerical analysis method is a common method for calculating the meshing stiffness of gears because of its simplicity. Numerical analysis methods include the Ishikawa formula method and the Weber energy method. In this paper, based on two numerical analysis methods, taking the involute spur gear as the research object, Matlab is used to calculate the comprehensive time-varying meshing stiffness of the two methods, and the results are compared and analyzed. The results show that the calculation accuracy of the Weber energy method is higher, which is closest to the results of the finite element method, but the calculation is more complicated. The Ishikawa formula method is more quickly calculated, and the Ishikawa formula method can be prioritized when the gear structure is simple.

Bionics is a subject that studies various excellent characteristics such as the structure, function and information control of organisms. These characteristics will give us a lot of inspiration in terms of mechanical design and will also provide new construction ideas for practical engineering applications. In this paper, based on the structural characteristics of the natural biological snake, a bionic snake-like robot with a meandering posture is designed. Bionic snake-like robot uses STM32F103ZET6 MCU and 16-way servo control board as the main control unit. The servo provides the driving force. Through the use of pulleys and various sensors, functions such as various attitude movements and real-time detection are realized. Using Solidworks software to carry out 3D modeling of the bionic snake-like robot and make a bionic snake-like robot model for experimental testing. The physical model size is 120mm*120mm*850mm. The results show that: on a relatively flat ground, the time for the bionic snake-like robot to move through a horizontal distance of 1m is about 5.50s. The bionic snake-like robot runs stably during the test and has no stuttering phenomenon.

Deep learning method is widely used in bearing fault diagnosis, but insufficient real working data and deviation of signal feature distribution often reduce the accuracy of fault diagnosis. To solve this problem, this paper proposed a diagnosis method combining transfer learning and convolutional neural network. The original vibration signal is transformed by wavelet to obtain the normalized time-frequency spectrum as the input of convolutional neural network model. Selecting a working state as the source domain to pre-train the network, and then make it applicable to other working states through transfer learning. The experimental results show that the new adaption network model can achieve a fault recognition rate over 99% for target task.

In the era of rapid development of railway industry, the switch machine is one of the important equipment to ensure the safe operation of trains, which has a pivotal strategic significance for the high-speed railway industry. The traditional switch equipment and switch machine fault diagnosis generally adopts the "experience method", this method has some problems, such as troubleshooting and labor time, fault diagnosis is not accurate, fault coverage is not comprehensive. In view of the above problems, this paper studies an intelligent tester, in order to reduce labor costs, improve diagnostic efficiency, and ensure the safety of railway system operation.

This study established 50% dummy front collision (FC) and 50% dummy rear collision (RC) simulation analysis working conditions to address the optimization problem of automobile seat skeletons, improve the overall performance of automobile seat skeleton structures, and avoid the problems of instability of multi-criteria decision results, non-uniform results of different multi-criteria methods. The gray relation analysis and fuzzy logic system were used to optimize the design of the automobile seat under FC and RC conditions, and the fuzzy logic decision system was adopted to make decisions on the optimal design solutions for the sample points under FC and RC conditions. Then, the two design solutions were rationally recombined to form the final optimal design solution. The final optimized design scheme reduced the quality by 19.2% and the cost by 25.7%. Afterward, this study compared the fuzzy decision method with TOPSIS decision methods and proved that the proposed fuzzy decision-making method is simple, efficient, convenient, and fast.

For various bearing states, the traditonal model has insufficient ability to extract important information, low accuracy and poor generalization ability of the model in complex environment.Therefore, a bearing fault diagnosis method based on CNN-BiLSTM-Attention is proposed. This method combines convolutional neural network (CNN) and bidirectional long and short term memory network (BiLSTM), adds the Dropout mechanism to the BiLSTM network to suppress the overfitting problem, then introduces the attention mechanism to automatically assign different weights to the BiLSTM network to improve the sensitivity and the ability to grasp different fault information. In order to verify the effect of this model, the Case Western Reserve University(CWRU) bearing fault dataset was used for experimental verification, the results show that the proposed model has higher accuracy and stronger generalization ability than other models in the multitask problem under complex working conditions.

In the elevator group control dispatching system, the deterministic analytical algorithm is still widely used in practical applications, but the traditional algorithm lacks self-adaptability to the elevator group control strategy, the processing efficiency of the call signal is low, and the selection of the elevator to be distributed is not flexible. To solve the above problems, traffic flow is introduced to identify traffic patterns and flexibly switch to optimize the stop sequence of call signals; Select the allocatable elevator flexibly, and use Poisson signal to simulate the passenger flow on MATLAB for simulation verification. The results show that after optimization, the owner's waiting time, congestion and elevator energy consumption are improved effectively.

The ability to solve the complicated and interconnected systemic CNC machine tool faults of traditional machine tool fault diagnosis systems are limited. As a research hot-spot in the field of artificial intelligence, the knowledge map has the ability to standardize the non -structured data such as expert knowledge and use it for fault diagnosis, which can realize the explanation of the cause of fault. This article proposes a method to construct self-optimizing diagnostic system of CNC machine tool based on knowledge graph. First of all, expert knowledge was used to build the ontology of the knowledge map, and clarify the entity and relationship type in the knowledge map. Then, BiLSTM-CRF Model was used for named entity recognition from non-structured text. After that, Attention-based BiLSTM Model was used for relation detection and classification based on the previous result. Eventually, the extracted entity and relationship can build a knowledge graph for the diagnosis of CNC machine tool fault. Based on this as a premise, the diagnostic system of CNC machine tool is realized.

To solve the problem of intercepting target with missiles for forward tracking, this paper proposes a novel forward tracking guidance algorithm based on adaptive fast dynamic surface sliding mode control method for interceptor missiles. Firstly, the guidance system model of forward tracking intercept is established based on the relative motion relation of missile-target and forward tracking interception principle. Secondly, in order to deal with the uncertain interference in the system and improve the guidance accuracy, the variable gain extended state observer (TVGESO) is used to estimate the interference in the model, on this basis, the forward interception guidance law is designed based on interference estimation and adaptive fast dynamic surface sliding mode control method. Finally, the simulation results verify that the proposed forward tracking guidance law based on the adaptive fast dynamic surface sliding mode can intercept the target in front of the target and has better guidance accuracy.

The frame is one of the most basic and important parts of the potato harvester, and it is the foundation of the existence of the entire harvesting machinery,whether the potato harvester can operate stably and safely relies on whether the frame has sufficient stability,therefore, the dependability study of the frame plays a critical role in the creation of potato harvesters because the frame is one of the most fundamental and essential components of the harvesting gear, and its stability determines whether the potato harvester can function safely and steadily. To this aim, SolidWorks software is used to model the rack in 3D, and then Hypermesh software is used to create the mesh,finally, ABAQUS software is imported to perform static and modal analysis of the frame,obtain the strain, strain and modal frequency of the frame during operation,determine the stability of the frame structure, combined with the range of excitation forces common to regular potato harvesters,analyze whether the rack is prone to resonance,if possible, find out the frequency of hazards that should be avoided during rack operation, so as to assure the security and reliability of the rack under standard operating conditions.

The legged robot has a strong ability to adapt to complex terrain. There are few researches on the adaptive fault tolerance of motion joint actuators of quadruped robots. Therefore, based on the basic principles of foot trajectory planning and gait planning, this paper plans the quadruped robot's foot trajectory and walking gait. Secondly, an adaptive fault-tolerant control law is designed for a quadruped robot's leg joint actuator fault. Finally, mathematical proof and simulation results show that the system can still safely complete the control task within the fault-tolerant range of the expected performance index after some actuator faults. This study provides direction for further research on the compliant motion of quadruped robots with partial actuator faults.

Research was carried out on the pure electric sport utility vehicle (SUV) transmission system coupled with 6-speed dual clutch transmission (DCT). Based on AVL Cruise software, the car is modeled, and the software simulation results meet the constraints. To further improve the performance, it is equipped with the joint simulation model of Isight and Cruise, adopts non-dominated sorted genetic algorithm II (NSGA-II), takes the transmission ratio of the pure electric SUV transmission system as the optimization parameter, the NEDC cycle The power consumption per 100 kilometers and the acceleration time to 100 kilometers under working conditions are optimized by multi-objective optimization calculations. The optimization results are entered into cruise software for review, and the outcome shows that, compared with before optimization, the power consumption per 100 kilometers of the NEDC cycle is reduced by 1.39kWh, and the economy is improved by 11.02%; the acceleration time to 100km/h is reduced by 0.81s, and the dynamic performance is increased by 7.03%

With the aim of addressing the challenge of diagnosing faults in the power supply and distribution system of on-orbit spacecraft, a fault diagnosis method based on Petri net is proposed. This approach consists of two components: a fault Petri net based on adaptive fuzzy Petri net and a verification Petri net based on basic Petri net. The methodology also includes the parameter setting and adaptive training adjustment methods that are suitable for the model. The objective factors and subjective factors are both weighed in the parameter setting to ensure that the description of potential fault components aligns with actual conditions. During the training and adjustment process, quantitative analysis and qualitative analysis are combined to improve diagnosis performance. Once the training of the model is completed, it can be used to independently localize and verify fault components, thereby reducing the manual effort required for fault diagnosis. Finally, the effectiveness of this method is demonstrated through an example of diagnosing faults in a spacecraft power supply and distribution system.

In order to meet the demand for lightweight and miniaturization of satellite-based laser communication loads, a rotating dual-optical wedge turntable based on the risley prism is designed. A pre-compensation scheme for achromatic is proposed and simulated to verify the feasibility of the inconsistent deflection angle between communication laser beam and beacon laser beam due to different wavelengths.

The Rapidly-exploring Random Tree (RRT) algorithm is widely used in robot path planning, but the slow convergence rate and poor quality of planned paths have always been its problems. To overcome these limitations, this paper proposes an RRT algorithm based on the improvement of the sampling space and local motion planner. Firstly, an adaptive hyperspherical sampling space is proposed, of which the radius is adjusted according to the minimum distance of the search tree nodes from the goal, which can effectively reduce the number of low-quality random sampling states; secondly, a local motion planner combining optimal motion policy and random motion policy is proposed, which improves the smoothness of the paths and accelerates the convergence. Simulations are conducted with a seven-degree-of-freedom space manipulator, and the results show that compared with the RRT* algorithm, the average search time of the improved RRT algorithm is reduced by 34%, the average path length is shortened by 2.5%, and the average path smoothness is improved by 59%, which verifies the effectiveness and practicality of the improved RRT algorithm proposed in this paper.

In order to solve the problem of low photoelectric conversion efficiency in solar power generation, a solar photovoltaic power tracking system based on PLC is proposed. This system can make directional adjustments when the sun's direction change, height and angle changes, so it can improve the conversion efficiency of photovoltaic modules. Finally, simulates with PVSystem, proves that the efficiency of using photovoltaic power tracking system is 30% higher than that of fixed solar cell system.

Domestication of coal machine gear reducer has become a trend, but domestic worm gear reducer has been serious fever, low transmission efficiency, worm gear wear is obvious, low life, especially the wear resistance of worm gear has become a "neck" technical problem in the industry. This paper analyses the fault existing in domestic worm gear and worm reducer, through the study of the worm and worm wheel material, processing, assembling and influence factors of lubrication and provides a selection of materials for the worm gear and worm gear reducer, worm gear and worm surface quality control Suggestions, worm gear and worm assembly and lubrication, etc., finally through the bench test and industrial test, The reducer can be used in the mine for more than 6 months without abnormal conditions, indicating that the development of the reducer is successful.

Recent years, the "Made in China 2025" strategy, the National "14th Five-Year Plan", the "14th Five-Year Plan for the Construction of Zhejiang Global Advanced Manufacturing Base", etc. have pointed out from the national and local levels to promote the digital transformation of China's manufacturing industry, build future factories, realize Intelligent Manufacturing Industry 4.0 to become a manufacturing power. [4] Based on this background, this paper expounds the implementation scheme of IoT Electronic "Intelligent Manufacturing" Factory based on MES technology combined with Flexible Lean Production Technology, Automatic Identification Technology, Automatic Testing and Assembly Technology, and Digital Information Technology through the intelligent manufacturing case of Hangzhou Zhiyuan Electronics Co., Ltd. The solution organically integrates ERP system, MES system, PCS system, etc., and forms an intelligent manufacturing scheme that integrates data information flows such as decision-making, execution, control adjustment, etc., through which the overall production quality and manufacturing efficiency of electronic products are improved. Besides, the flexibility is increased and the manufacturing cycle is also significantly shortened. It provides a successful exploration of theory and practice for the implementation and promotion of multi-variety, small-batch electronic intelligent manufacturing based on MES system and IoT technology.

The rolling bearing data under different working conditions show different distribution, resulting in the classifier trained cannot meet the task of multi-condition fault diagnosis. To solve this problem, a domain adaptation method based on multi-domain features of rolling bearings was proposed. Firstly, the original signal is decomposed by parametric optimization VMD, singular value and permutation entropy are extracted, and the time domain features of the original signal are combined to form multi-domain features. Secondly, multi-domain features are embedded into Grassman manifold space by GFK to achieve feature reduction and optimization and eliminate redundant information. Thirdly, the manifold characteristics of source domain data and target domain data are dynamically aligned. Finally, the crossdomain classifier is trained to realize cross-working condition fault diagnosis of rolling bearings. The results show that the proposed method can achieve better performance than the traditional intelligent fault diagnosis method and domain adaptive method in different working conditions.

In environments with harsh environments, high electromagnetic interference, and poor data channel quality, wireless laser power meters face the risk of data loss and data bit errors when measuring laser power. The wireless data transmission module works on a free channel using open standards, and is vulnerable to attacks, resulting in data leakage. In view of the above problems, this paper designs the communication data frame format of the PC end and the data acquisition module end for the wireless laser power meter data acquisition system. The TEA data encryption algorithm and the CRC check algorithm based on the look-up table method are added to the data frame. For the voltage noise and abnormal values collected by the data acquisition module, this paper uses a real-time low-pass filter algorithm to filter out high-frequency noise, and designs a sliding window algorithm to smooth the power curve and remove power abnormal values. The communication protocol and data processing algorithm designed in this paper realize the data verification, error retransmission and data encryption of the wireless laser power counting system, ensure the data reliability and data integrity during the data transmission process, and realize real-time noise reduction and power curve smoothing.

In the study of harmonic and negative sequence current of high-speed railway traction power supply system, many literatures have the regret of insufficient completeness of simulation system. In this paper, the negative sequence current distribution of the system under no-load, traction and regenerative braking conditions is analyzed in detail from the design of converter to the simulation operation modeling process of EMU. The negative sequence characteristic waveforms under various working conditions are obtained. In addition, the simulation results show that the regenerative braking condition is rich in harmonics, and the generated energy will be used by the locomotive under traction. These poor energy will threaten the current collection and commutation process of high-speed trains. According to the waveform in this paper, the trend of negative sequence current can be summarized and used for the prediction of negative sequence current. The negative sequence current under different working conditions can realize the accurate classification and identification of the working conditions, so as to divide and rule the working conditions, and more reasonably avoid the occurrence of accidents such as generator burning caused by negative sequence problems.

With the introduction of energy internet, Multi-energy coupling and complementation properties of the integrated energy system in the park provide more space for system optimal dispatching, but the carbon emissions brought by the purchase of power from the external network are difficult to estimate, which brings challenges to the low-carbon operation of the integrated energy system in the park. In this paper, the carbon flow of external power grid is accurately calculated, and a two-layer optimal dispatching model of PIES low carbon economic dispatching is established. The results show that the proposed model can optimize the distribution of carbon flow in PIES, remove the carbon deficiency in the system and enhance the environmental protection of PIES.

This paper deals with a common problem in the reliability testing of aviation products—reliability assessment with zero failure data. Because the conventional method is excessively conservative, a reliability estimation method that introduces the lifetime dispersion of expert judgments is proposed in this paper. It is defined as the ratio of the maximum lifetime with a probability of 99.73% to the minimum lifetime. The performance of the proposed method is analyzed and compared with the conventional method through a Monte Carlo simulation study. The results show that the proposed method is superior in accuracy and robustness. In particular, the method performs better in the reliability assessment of aviation products. Finally, an application case study is conducted to illustrate the application of the proposed method.

The performance of the key parts of the elevator weights carrying robot determines the security of the entire device. The traditional theoretical calculation method may have problems such as low calculation accuracy, long time, large data error and inaccurate calculation results., the paper proposes to use the finite element analysis method to analyze the key parts. The finite element analysis of the bearing capacity and bending fatigue of the key parts of the elevator weights carrying robot is carried out by using the three-dimension modeling software simulation module. The stress-strain analysis results are obtained by means of three-dimensional modeling, finite element model establishment, material performance analysis and stress analysis of key parts. The results did not exceed the maximum allowable stress of the material, and the maximum displacement was within the allowable range, which met the analysis requirements and realized the reliability and safety detection of the key parts of the Carrying Robot. The test results meet the required requirements.

This paper explores the enhancement and optimisation of cabin service mode from the perspective of improving passenger flight experience and cabin service intelligence, proposes the innovative design of cabin intelligent service robot product, and conducts research on the industrial design requirements and design practices of cabin intelligent service robot. The aim is to explore new models of cabin service and intelligent cabin products to meet the changing needs and challenges, break the existing aircraft cabin service model, and bring more possibilities to the aviation industry.

In this paper, new technologies and algorithms such as machine learning and swarm intelligently optimize algorithm are introduced into the condition monitoring of wind turbines, and the method of temperature trend analysis is used to monitor the condition of wind turbines. Firstly, in order to solve the problems of slow convergence speed and easy to fall into local optimum during the training of wavelet neural network, an improved method of Flower Pollination Algorithm optimized wavelet neural network is proposed, and the temperature model of wind turbine is established, and the model is used to carry out temperature prediction, and then the state of the wind turbine is obtained by analyzing the temperature residual, so as to achieve the purpose of online temperature monitoring.

To improving the resource utilization and data processing efficiency for low-voltage power distribution in new-type power system, this paper first investigates a cloud-edge collaborative edge processing architecture for low-voltage power distribution. Then, a cloud-edge collaborative data processing optimization method for low-voltage power distribution is proposed to optimize the data processing mode and computing resource allocation strategies. Simulation results show that the proposed method can effectively ensure the data processing efficiency and stabilization for low-voltage power distribution.

The hydraulic system of the hydraulic support truck for coal mines is prone to failure during operation, and the failure of the hydraulic system is not handled in time, which has a serious impact on the safety construction of coal mining projects. Aiming at this problem, a new fault diagnosis method of hydraulic system is proposed. According to the working principle of the hydraulic system of the hydraulic support truck, establish a mathematical model for fault diagnosis of the hydraulic system; extract the fault time domain signal characteristics of the hydraulic system, and obtain the mean and variance of the fault samples; analyze the operating state and operation mode of the hydraulic support truck, and analyze the internal hydraulic system. Comprehensive fault diagnosis. Through the experimental analysis, it can be seen that the designed hydraulic system fault diagnosis method can quickly complete the fault diagnosis in a short time, and the accuracy of the diagnosis results is above 95.27%, which is highly feasible.

There is growing demand of biological tubulars considering the scarcity of acceptable donor tissues for organ transplantation. 3D bio-printing organs has proven to be a lifesaver for tubular illness patients. However, most bio-printers are based on pneumatic actuation system, which have significant ink supply control delay due to the high air compressibility. This study proposes and describes a novel piston-actuated bio-printer for tubular structure, including background information, software, and hardware. It is validated that this bio-printer successfully printed different sizes of tubular structures with good position accuracy and ink supply controllability, which shall support cultivation of bio-tubulars of future use.