Control of distributed electrostatic microstructures

A control method for the distributed electrostatic actuator has been studied. The actuator consists of many driving units. Each driving unit has wave-like electrodes, which are insulated and pulled to each other by the electrostatic force. The deformation of this actuator depends on the electrostatic force, the elasticity of the structure and the external force. A macro model of the actuator was developed to verify its motion. In this actuator the apparent compliance can be controlled by a feedback control system using capacitive displacement sensing and electrostatic driving. Two types of actuator were studied. One is the common-electrode type in which both sensing and driving are performed by the same electrode. The other is the separated-electrode type in which driving electrodes are separated from sensor electrodes. It was confirmed that the apparent compliance can be changed by the feedback gain.