Design and Modeling of an Efficiency Horizontal Thermal Micro-Actuator with Integrated Piezoresistors for Precise Control

Abstract

An integrated system made up of a double-hot arm electro-thermal microactuator and a piezoresistor embedded at the base of the 'cold arm' is proposed. The electro-thermo-mechanical modeling and optimization is developed to elaborate the operation mechanism of the hybrid system through numerical simulations. For given materials, the geometry design mostly influences the performance of the sensor and actuator, which can be considered separately. That is because thermal expansion induced heating energy has less influence on the base area of the 'cold arm,' where is the maximum stress. The piezoresistor is positioned here for large sensitivity to monitor the in-plane movement of the system and characterize the actuator response precisely in real time. Force method is used to analyze the thermal induced mechanical expansion in the redundant structure. On the other hand, the integrated actuating mechanism is designed for high speed imaging. Based on the simulation results, the actuator operates at levels below 5 mA appearing to be very reliable, and the stress sensitivity is about 40 MPa per micron.