Multi-physics Modeling and Calibration for Self-sensing of Thermomechanical In-plane Microactuators Multi-physics Modeling and Calibration for Self-sensing of Thermomechanical In-plane Microactuators

by Teichert, Kendall B

As technology advances and engineering capabilities improve, more research has focused on microscopic possibilities. Microelectromechanical systems (MEMS) is one area that has received much attention recently. Within MEMS much research has focused on sensing and actuation. This thesis presents work on a particular actuator of interest, the thermomechanical in-plane microactuator (TIM). Recent work has shown the possibility of a novel approach of sensing mechanical outputs of the TIM without ancillary sensors. This sensing approach exploits the piezoresistive property of silicon. However, to implement this approach a full model of the TIM would need to be obtained to describe the physics of the TIM, as well as development of a calibration approach to account for variations between devices.

This thesis develops a multi-physics model of the TIM to realize this sensing approach. This model determines the mechanical state of the TIM using the same electrical signal that actuates the TIM. In this way the TIM is able to operate as a self-sensing actuator. To allow this multi-physics model to be tractable, work was done to simplify the thermal modeling of the TIM. A preliminary calibration approach was developed to adequately compensate for variations between devices. Thermal modeling and calibration were coupled with mechanical modeling and a developed sensing approach to form the full multi-physics model of the TIM. Validation testing of the model was performed with a modified calibration approach which showed good correlation with experimental data.