In order to obtain the inherent law of the structure and performance of the SMA actuator of the bionic flexible dexterous hand. Four phase transition temperature parameters of SMA wire were obtained by temperature test. The Brinson constitutive model was used to describe the material relationship of SMA. The finite element model of SMA mechanical properties was established by user material subroutine (UMAT). The validity of the secondary development was verified by comparing the results with the literature. Based on this, the parametric finite element modeling and simulation of SMA actuator were carried out, and the influencing factors of mechanical properties of SMA actuator were analyzed. The results show that the SMA wire diameter of the dexterous hand actuator has a great influence on the performance of the actuator, while the structural parameters such as the winding spacing and the actuator diameter have little effect on the driving performance of the SMA wire. The pre-stretching force and output force of the actuator increase with the increase of the diameter of the SMA wire. The research results provide a reference for the design of related SMA actuators.
In modern manufacturing, the in-process measurement of complex surface of cylindrical gear is critical and challenging, and is directly associated with subsequent assembly and terminal gear quality. 3D geometric measurements of gear are ones of the crucial fundamental quantities to ensure their conformity to design specifications serving a range of industries, from shipping, automotive and aerospace industries to house applications. In this paper, an automated sampling path planning model is designed in order to obtain a loss cost sampling path by consider of the complex surface of cylinder gear. The high-precision full information model of tooth flank is also being established, which depends on the measurement procedure and the measurement uncertainty. A series of experiment on several typical cylindrical gears were carried out to demonstrate this automated path planning technique and the final geometric measurement accuracy. On the other hand, an commercial 3D geometric measuring system was also introduced, which has two degrees of laser scanner. Those scanning paths generation have been proven to be amenable for practical purposes through many tests so that it might be applicable to achieve 3D geometric measurements of large gear
In this paper, a submicron linewidth measurement method based on computer microscopic imaging technology to improve the measuring precision is proposed. Firstly, the microscopic image of the standard line pair is taken at the magnification M, and the pixel representing distance (PRD) of the microscopic image is calibrated. Secondly, the noise of the image is eliminated by the median filtering technology, and then the minimum ambiguity criterion of direction information measurement is used to quickly identify the edge boundary points of linewidth. Then, the edge points of the linewidth are fitted and filled to form a regular geometry shape, which can be accurately located by using the cascaded Hough transform algorithm. Finally, in order to verify the validity of the method, several representative linewidths are selected on the standard sample plate to repeat the measurement nine times, the experimental results show that for line width greater than 2 μ m, the error of measuring linewidth with the method studied in this paper is less than 0.1 μ m. Therefore, this method reveals the possibility of high-precision measurement of linewidth through microscopic images, and makes it be a much better option to be employed for further micro-nano structures analysis applications.
In order to obtain high precision optical constants at in the ellipsometry measurement process, an optimization algorithm for solving the complex refractive index of nano films at visible wavelength is proposed. To improve the convergence rate and the ability to escape from local optimum of original algorithm, an Improved Particle Swarm Optimization (IPSO) has been proposed to deal with and analyze the ellipsometry parameters, this method combines the evolutionary algebraic attenuation factor with the adaptive genetic algorithm. The algorithm is used to calculate the film parameters of silicon dioxide nano film thickness standard template with standard value of 100.4±0.3 nm in this paper. The results show that the relative error of the calculation results of the optical constants refractive index error is less than 0.1 at visible wavelength. At the same time, it is verified by experiments that the IPSO algorithm model can effectively optimize the number of iterations and has the advantages of fast convergence speed and high measurement efficiency.
This article adopts comparative measurement means to realize the intelligent measurement of gauge blocks through micro range high-precision inductance sensor based on the principle of inductance micrometer. The gauge block intelligent measurement system mainly includes intelligent detection system and data management system. The experimental results of indication error, measurement repeatability and time drift of the measurement system show that the system can measure gauge blocks with high accuracy and efficiency.
In this paper, a 2-D sizing measuring system of regular particles is developed for characterizing the shapes by simultaneously measuring their length and width. Due to the multi-regulars shape of particles, it is usually required in situ 2D semi-automatic imaging analysis technique to describe their different shapes. In our works, edges of particles in binary image are first detected based on automatic threshold decomposition of the original gray-scale image. Then, the internal holes are filled in some individual detection region. In order to separate from different regular shapes, a selected threshold for the rectangularity filter has been applied. Then, by use of Euclidean distance map (EDM), the size measurement of individual particle is calculated. Finally, a series of experiments on these selected electron micro graphs , which contains particle with sizes from 10nm to 200nm, are respectively carried out to verify the performance of previous image analysis technology on our developed software. Those results are most promising for on-machine applications in naon-dimensional measurement of regular particles.
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