Analysis of Closed-Loop Control of Parallel-Plate Electrostatic MicroGrippers

A design of a high-force-output large-deeection parallel-plate electrostatically actuated microgripper is described. This design uses polysilicon as a structural material and may be fabricated using an IC-based surface machining process. This paper shows that by using a position feedback controller, this microgripper can be stabilized in theory, which is supported by computer simulations. Preliminary data from fabricated micro-grippers also supports the mathematical model for the open loop system, although pull-in voltages (50V to 100V for gaps of 80 to 100 m 2) are generally lower than predicted, probably due to the inherent instability of the electrostatic system. Further experiments are in progress to evaluate the open-loop system and the closed-loop system.