Stiffness match between electro-thermal micro-actuators and compliant amplifiers

Stiffness mismatch between electro-thermal actuator and the attached micro leverage severely ruins the performance of their combination. This paper analyzes the stiffness relationship between them theoretically and finite element method (FEM) is used to carry out simulation. This combined structure is simplified as a model of two springs connected in series. The results show that the stiffness ratio of the micro-actuator and the micro leverage significantly affects the output performance of the system. In addition, the load line method is used to explicitly explain the stiffness match design between two compliant mechanisms. In the end, prototypes were fabricated on silicon-on-insulator (SOI) wafer with deep reactive ion etching (DRIE) technology and tested. The test and analytical results well coincide with each other.