The authors propose the development of a three-degree-of-freedom hand vibration compensation device, featuring a compliant mechanical structure incorporating three stack-type piezoelectric actuators. Inspired by the Stewart-type mobile platform, the system employs this design to manipulate a laser beam in two directions. Moreover, it facilitates an optimal axial stroke, ensuring precise laser beam focusing. This paper details the comprehensive process, encompassing modeling, simulation, and experimental trials, of a compliant mechanical amplifier designed for powering an innovative laser scalpel prototype. The active tremor damping capability of the proposed system is thoroughly examined, shedding light on its potential applications in medical settings. The authors employed a mechatronic approach, integrating mathematical models, MATLAB simulations and finite element analysis (FEA). Mathematical models were utilized to capture the static deformation of the compliant mechanical structure, providing a theoretical foundation for the subsequent stages of development. MATLAB simulations were then conducted to validate and refine the theoretical models, ensuring their accuracy in representing the system's behavior under various conditions. To further enhance the robustness of the design, finite element analysis (FEA) was employed to validate the structural integrity and performance of the proposed device. This simulation tool allowed for a detailed examination of stress distribution, deformation patterns, and overall mechanical response, guiding refinements to optimize the system's functionality. Expanding upon this, the research underscores the significance of mitigating hand tremors in surgical procedures, emphasizing the practical implications of the developed device.
The article proposes the creation of an image processing application dedicated to laser spot detection, along with an experimental setup designed for the scrutiny of laser spot control. In the conclusive phase of testing the optomechatronic device, a specialized setup was intricately crafted for the precise analysis of the laser spot's position. This experimental arrangement involves the device projecting a laser spot onto graph paper positioned 1.5m away. Horizontally positioned on the shaker, controlled vibrations are imparted to the base of the laser scalpel prototype. A high-resolution video camera captures the laser spot's movement at 2160p and 60 frames per second. Following the tests, MATLAB is employed for video processing, revealing the nuances of the laser spot's motion. The initial test introduces a 10 Hz sinusoidal signal to the shaker, inducing oscillations in the laser spot on the graph paper. A brief video, comprising around 660 frames, is recorded, and subsequently processed to validate the optical processing procedure. This comprehensive methodology establishes a robust foundation for assessing the device's performance, ensuring precise compensation for induced vibrations during laser operation. The experimental findings highlight the efficacy of the proposed mechanism in augmenting the precision and stability of laser-based tools, thereby laying the groundwork for advancements in minimally invasive medical interventions.
The paper presents an optical method of damping vibration present in manually operated laser surgical devices. Considering the frequency range of the physiological tremor of 5-15Hz, the design of two compliant positioning mechanisms on 2 axes was made, which will have the role of supporting and moving the focusing lens of the laser device. A couple of compliant structures were subjected to static and dynamic finite element analyzes (modal analysis) to determine the displacement-force characteristic and resonant frequencies, eliminating the risk of operating in the frequency band of physiological tremor. Finally, the structures were teste in laboratory for final experimental results.
As tremor is a condition which occurs in all individuals, its effects can have a big impact on person’s everyday life. If we are considering professionals who rely on manual labor to perform precise activities, tremor becomes the source of many problems. Moreover, as specific literature highlights, tremor occurs mostly at hands and fingers level. The aim of this paper is to provide an enhanced controller for a precision positioning system used in laser medical instruments. The controller shall be tuned in such way to overcome the constraints imposed by electromagnetic actuators, yet providing high precision positioning, considering the application requirements (approximatively 50 µm maximum displacement).
KEYWORDS: Actuators, Mirrors, Prisms, Electromagnetism, Magnetism, Laser systems engineering, Control systems, Scanners, Chemical elements, Signal processing
The stabilization of portable laser systems is of major importance for improving performance and ensuring high mobility of devices. These systems can be grouped into two classes: resonant and non-resonant, each requiring different approaches. The article presents the conceptual and physical results of research, focused on the industrial application of a stabilization solution in the field of portable laser equipment used in the medical field. The proposed solutions to the major problems encountered are presented: mobile system motion detection and correction signal extraction, mechatronic positioning system design, feedback loop design, concept of a system performance certification stand. Aspects regarding the optimal actuation solution are discussed, comparing the piezoelectric, electrodynamic and electromagnetic ones. These are analyzed for gauge conditions imposed in terms of accuracy, range, thermal stability, the presence and size of nonlinearities and hysteresis. A major problem in these portable systems is their miniaturization. A scanning solution is presented based on the use of LIGA-Laser technology for mechanical microstructures and micromagnets, in bulk or 2D array structure manufacturing, which interact with planar coils. The solution has a practically proven improvement, not used so far in scanners, respectively a structure with two coupled degrees of freedom for each direction of movement, on the principle of dynamic absorber. The preliminary results for the numerical signal processing and the mechatronic construction of the dynamic positioning system of the entire laser assembly are also presented, as a possible option for the use of small size sources, having the advantage of an easy autofocus.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.