Research On Optimizing Design Method And Experiment Of Fully Compliant Mechanism

MEMS(Microelectromechanical Systems) has developed rapidly in recent years. However, its fundamental theoretical researches lag the design and fabrication process of MEMS, and become a bottleneck problem, impeding the development of MEMS. The research on mechanical properties of MEMS materials is one of MEMS fundamental theoretical research fields. Affected by fabrication processes and scale effect, mechanical properties of MEMS materials may be different from those of macroscale, and should be studied deeply to provide foundation for the design of MEMS. In order to obtain the mechanical properties of MEMS materials, it is necessary to develop a test instrument, which is specially used to measure mechanical properties of MEMS materials.This dissertation aims to solve two key problems on optimizing design of mechanism and driving technique for the development of a test instrument for measuring mechanical properties of MEMS materials. A 3-DOF redundantly-actuated planar parallel FCM(Fully Compliant Mechanism) actuated by PZT is adopted as the mechanism type of the mechanical body of the test instrument. This mechanism can improve force transmissibility performance of the FCM through the redundant actuation. The test instrument consists of four parts namely precision positioning subsystem including mechanical body and PZT driving power, specimen clamping subsystem, load and displacement measuring subsystem and measuring and controlling subsystem. In this thesis, the following studies on precision positioning subsystem are completed: (1)Based on the related literatures home and abroad and the requirement of measuring mechanical properties of MEMS materials, the whole design plan for the test instrument is presented. Then, the four subsystems are introduced in brief, and the precision positioning subsystem is expounded detailedly.(2) FCM is studied deeply and the mechanism type of the mechanical body is determined. Beginning with the rigid mechanism of the mechanical body, an optimizing topology analysis of the mechanism is discussed. The following part is to establish a kinematics model, which provides the foundation for the design of FCM. (3)To get the optimal kinematics and force transmissibility performance of the mechanism, GA(Genetic Algorithms) is employed to optimize its parameters. Finally based on the optimization results, the FCM is designed and manufactured.(4) Combining with the characteristics of mechanical body and PZT actuator, a four-channel PZT driving power is designed, which has several selectable input modes, a direct output voltage ranging between OV and 200V. The experiment results prove that the power can meet the needs of the PZT actuator. The design methods of the FCM and experiment conclusions of PZT driving power presented in this dissertation are helpful for the development of test instrument for measuring mechanical properties of MEMS materials and have laid a solid foundation for the future research and development.