Modeling the Response of Surface Micromachined Thermal Actuators

Abstract

Thermal microactuators, devices that use the principle of thermal expansion to amplify motion, have several advantages in comparison with other actuators used to motivate surface micromachined components such as rotary microengines. They provide higher output forces and have simple geometries. Accurate steady-state and transient modeling of such thermal actuators provides a tool for design optimization to obtain better actuator performance. This paper describes the development, modeling issues and results of a three dimensional multiphysics non-linear finite element model of a surface micromachined thermal actuator. The simulation results are compared with experimentally measured data. Reasonable agreement is observed for static actuator deflection response. The measured transient response is observed to be significantly slower than that predicted by the finite element model.