Optimization of Polymeric Electro-Thermal Micro-Actuator for Various Criteria

This paper explores the possibility of advancing the actuation capability of a thermal actuator design, based on the polymeric SU-8 epoxy with embedded silicon (Si) microstructures. Theoretical models for the actuator design are established in an attempt to evaluate the thermoelastic and thermal time responses for the composite design. Thereafter, design criteria and design variables are identified. Optimization of the composite design results in an optimum design that improves the energy density, but does not compromise the thermal response time. The optimum design (70-30% SU-8/Si) has a 20% higher energy density than that of the initial design (50-50% SU-8/Si) and a 20% decrease in thermal response time. It is noted that the optimum energy density for the composite is 2.6 times higher than pure SU-8. Keywords: MEMS actuator, thermal actuator, artificial muscle, micro-actuator, polymeric actuator.