Control of an electro static micro actuator in servo bandwidth higher than it's resonance frequency

In the case when an electro-static micro actuator has enough high mechanical resonance frequency for its goal servo bandwidth, it can be positioned adequately by open-loop control. But, for design limitations, if it have not sufficient stiffness, closed-loop conrol is needed. Additionally, according to driving mechanism, static electric force is changed not only by an applied voltage but also by its own position. In this case, a control system that have real-time position sensor need to be developped. We suggested a position sensing method using its capacitance change, and evaluate the posibility of controller using this method.