Abstract: A MEMS electrostatic piston-tube actuator that provides 4 degrees of freedom (4-DOF) motion is disclosed. The actuator comprises of an inner and an outer MEMS structure. The inner MEMS structure comprises of an inner moving stage (rotor) and an inner fixed frame (stator). The inner rotor comprises of a central load stage, a plurality of rotary comb drive electrodes surrounding the central rotor. The outer MEMS structure comprises of an outer moving stage (outer rotor) and outer stator frame. The outer rotor holds the entire inner MEMS structure and is rigidly attached to it through a fixed periphery of the inner MEMS structure. The outer rotor comprises of a plurality of through openings (tubes) and attached to a fixed outer periphery through a plurality of mechanical springs. A load set on the central stage can be controlled in 4-DOF comprising of translational and rotational motions of roll, yaw, pitch, and z-axis translation.

Abstract: A MEMS electrostatic actuator that provides 5 degrees of freedom (5-DOF) motion is disclosed. The actuator comprises of an inner, a middle, and an outer MEMS structures that are nested with respect to each other. Each of the structures comprise of a plurality of rotors and stators. The rotors further comprise a plurality of moving capacitive electrodes which engage with a plurality of fixed capacitive electrodes in the stators to provide a variety of translational and rotational motions.