Nonlinear Control of an Electrostatic Micromirror Beyond Pull-In With Experimental Validation

This paper is aimed at demonstrating the potential benefits of applying nonlinear control techniques to a type of microelectromechanical system, namely, electrostatic micromirrors, in order to extend their stable operation range, enhance the system's performance, and allow controller tuning and system operation to be performed in a systematic manner. A nonlinear tracking control based on feedback linearization and trajectory planning has been developed. Aspects essential to the implementation, such as the prevention of devices from destruction due to contact, modeling and sensing schemes, the influence of the dynamics of the driving circuit on performance, and the device characterization, have been thoroughly addressed, and practical solutions have been proposed. The experimentation is performed on a setup built with low-cost commercial off-the-shelf instruments and components in a laboratory environment. The experimental results show that the developed control system can achieve stable operation beyond the pull-in position for both set-point and scanning controls.