Study On Topology Design And The Related Problem Of Electrthermal Microgripper

Microgripper is one of the key elements in MEMS, and acts as an important role in microrobotics and microassembly technologies for handling and manipulating microobjects. To research and develop microgripper applied in microoperation and microassembly is a key factor for bringing about industrialization in MEMS. Because of its importance and widespread application, in recent years has become one of important fields of micro-nano technology research. However methods for designing microgripper have not been studied extensively. The overall design scope of most microgrippers developed in recent years lack a systematic mechanism design approach. This thesis is focused on design of microgripper, as well as the related researches including simulation, fabrication and test are done.After analyzing the current research achievements, and combined with the requirements of MEMS, in this thesis, the microgripper is based on electrothermal principle. V-shaped beam array electrothermal microactuator is adopted to generate displacements for microgripper, and the micropper is designed by topology optimization and pseudo-rigid-body model.The mathematics model of multiple loading case is established based on strain energy (SE), in which, a dummy load is applied at the output point to model the resistance of the workpiece, and the compliance is regarded as the objective function. Two kinds of compliant microgrippers with amplification ratio of 7.4 and 10 are obtained by OC (Optimization Criteria) method for solving the model. As well as, the mathematical model of topology optimization is established based on the principle of mutual potential energy (MPE), in which, the ratio of MPE to SE is regarded as the objective function. A compliant microgripper with amplification ratio of 18 are obtained by the method of moving asymptotes (MMA) for solving the model.According to property of the electrothermal microgripper, the topology requirements for gripper mechanism are summarized. Six-bar, eight-bar and ten-bar mechanisms are obtained with the type synthesis of a kinematic chain. And four kinds of microgrippers with amplification ratio of 50, 20, 18 and 6 are obtained based on the pseudo-rigid-body microgripper mechanisms, on that obtained by pseudo-rigid-body model based on the rigid mechanisms.Performance analysis of V-shaped electrothermal actuator and the electrothermal microgrippers with noval structures is achieved by Coventor Ware and Ansys. The geometric parameters of V-shaped electrothermal actuator are discussed, and appropriate parameters are confirmed. In respect of polysilicon and nickel electrothermal microgrippers, the changes of...