Nonlinear control of an electromagnetic polymer MEMS hard-magnetic micromirror and its imaging application

In this paper, a nonlinear feedback control algorithm is proposed to improve the performance of an electromagnetic actuated polymer MEMS hard-magnetic micromirror. The enhanced performance and effectiveness of the proposed algorithm are verified experimentally through National Instrument Field-Programmable Gate Array hardware. Considering the critical requirements in the micromirror-based optical switching applications, the set-point regulation tests are performed to investigate the transient and positioning performance of the system. The proposed scheme provides enhanced transient response when compared to traditional proportional-integral-derivative control. Compared with open loop control, the experimental results of set-point regulation have demonstrated that the 95% setting time is shortened from 50 to 10 ms while the 30% overshoot is eliminated with high positioning performance by using the proposed scheme. A magnetic micromirror-based laser scanning system is developed to verify the tracking and imaging performance of the closed-loop system with the proposed scheme. The results confirm that the closed-loop controlled magnetic micromirror follows the given sinusoidal and triangle trajectories precisely with the proposed scheme and an image of the scanned target is obtained.