Self‐sensing estimator for micromachined electrostatic actuators and parameters’ optimisation

Abstract

Parallel plate actuators (PPAs) are widely used in micro-electro-mechanical systems. Control strategies for PPAs often require displacement and velocity feedback that may be measured with various sensing techniques, which may require additional structures or distort the steady-state behaviour. An alternative approach of designing an estimator using the measured voltage across the PPA without additional sensing structures and distortions is proposed in this work. This novel method can improve the performance and reduce the device's footprint with full-state (displacement and velocity) feedback information, using a series resistor. A system model using this configuration is investigated. The observability of this self-sensing technique is analysed using a small signal model. Then, a singular value decomposition is applied to examine how to further improve the observability by choosing appropriate parameters. Simulation and numerical studies were performed which validate this method.