Angle tracking of MEMS hard-magnetic micromirror by PID control

Electromagnetic actuated torsional micromirror fabricated using Micro-Electro-Mechanical-Systems (MEMS) technology is a fundamental building block for many applications. The main purpose of a torsional micromirror system is actuated by current to provide a deflection angle, so angle control of the micromirror system is of prime importance. An electromagnetic MEMS micromirrors have been designed with the composite of PDMS and Nd-Fe-B micropowder (MQFP-12-5) and actuated by external spiral coils. Considering the requirement of high performance in optical switching applications and poor performance at the open loop response, proportional, integral and derivative (PID) controller is designed to improve transient response. The experimental results of angle tracking have demonstrated that the 95% setting time is shortened from 50 to 15 ms while the 70% overshoot is improved obviously with high positioning performance by using the proposed scheme. The results also confirm that the controlled magnetic micromirror follows the given angle precisely.