Modeling And Optimization Of Stiffness And Frequency Adjustable Micro-servo Mechanism

In this paper, on the basis of analyzing the existing structure of micro-servo mechanisms, to eliminate the error in the manufacturing process and better adapt to the changing working conditions, a stiffness and frequency adjustable micro-servo mechanism based on spring type flexure hinges and stress stiffening is designed. With the theoretical guidance of flexure hinges theory, data fitting and other numerical analysis methods, the theoretical model of bearing stiffness and feeding frequency of the micro-servo mechanism is built. Then develop the size optimization software module of spring type flexure hinges using MATLAB optimization toolbox. Based on researching on the key technologies of the problem, the following results have achieved:(1) Design a micro-servo mechanism with the piezoelectric ceramics acting as the driving element and the spring type flexure hinges acting as the amplifying and guiding element. The stiffness and natural frequency of the structure can be changed by adjusting the tension exerting on the spring leafs, so the mechanism is designed with stiffness and frequency changing function.(2) The stiffness of flexure hinges beam is simulated by multi-physics finite element analysis software COMSOL. And combined with the data fitting and stiffness equaling methods, the stiffness formula of one end fixed and the other end guided flexure hinges beam is given. Through the software testing, the error is less than 3%.(3) Deduce the calculation formula of bearing stiffness and feeding frequency of the micro-servo mechanism based on flexure hinges. And result is verified by finite element analysis software with the error within 10%.(4) Based on MATLAB GUI interface, the theoretical relationship between the property of the mechanism and size parameters is expressed intuitively through the interface, and optimizing the sizes of the mechanism at given bearing stiffness and feeding frequency based on MATLAB optimization toolbox. The result is tested by the software, the error is within 10%.(5) To meet the greater adjusting range of stiffness and frequency, a stiffness and frequency adjustable micro-servo mechanism based on mobile bearing is invented. The stiffness and natural frequency of the mechanism can be changed by adjusting the effective length of the spring leafs. The theoretical model between the frequency and the effective length is built and verified by software with the error less than 3%.