Closed-loop adaptive control for electrostatically driven torsional micromirrors

Abstract

We demonstrate a closed-loop adaptive control scheme for achieving accurate positioning and trajectory tracking of an electrostatically driven torsional micromirror. Compared to the conventional proportional-integral-derivative (PID) controller, the proposed adaptive self-tuning controller has advantages of on-line compensating parameter variations and model uncertainty of the torsional micromirror, resulting from fabrication imperfections. Numerical simulation results utilizing MATLAB indicate that the proposed adaptive controller has a better transient response and can more precisely follow the reference trajectory, compared to the PID control scheme. The torsional micromirror is designed and successfully fabricated using surface micromachining processes. Real-time experimental results demonstrate that the proposed adaptive control is feasible and can improve the performance of the micromirror. © 2005 Society of Photo-Optical Instrumentation Engineers.