Position Sensing of Electrostatic MEMS Actuator

The paper deals with a sensing technique for electrostatic MEMS (Micro-Electro-Mechanical Systems) actuator with an associated mechanical system. The weight of the load and the torsional elasticity form a mechanical resonant system with a relatively high quality factor, which is prone to parasitic oscillations. The paper studies a damping feedback loop with an all-electrical sensing of the drive angular position. The sensing bridge works with any comb drive not requiring dedicated fingers to sense the position. An experimental realization of the loop with dual-axis mirror drive is presented.