An electrostatically suspended contactless platform

Abstract

Electrostatic suspension of a silicon disk with explicit control of the lateral translational degrees-of-freedom is reported. The transduction subsystem configures electrode pairs to exert electrostatic forces on the disk and to also measure differential capacitances related to the disk position. Disk sidewall forcing electrodes are not necessary to control the disk’s lateral position because tilting the disk relative to the plane of the electrodes exerts lateral forces on the disk. Despite the fact that the disk’s lateral and angular degrees-of-freedom are strongly coupled, the system is not strongly stabilizable using only the disk’s vertical position and tilt estimates derived from electrode–disk gap measurements. Nevertheless, a stabilizing controller is proposed and lateral position measurements are added for regulating the disk’s in-plane position. Extensive experimental results corroborate the model and analysis.