Resonant stator actuation of gear coupled Ultrasonic Motors

This paper presents, for the first-time, actuation and direction control of multiple gear-coupled surface micromachined ultrasonic motors. Using three Whispering Gallery Mode Micro Ultrasonic Motors (WGMMUMs) with different flexural resonances, the center motor motion is controlled to rotate clockwise (CW) and counter-clockwise (CCW) direction at controlled rotation speeds. The bulk-PZT actuates the hub-stator at its resonances, some of which are whispering gallery modes and a rotating wave generated on the stator couples shear forces to the air between the stator and the rotor causing a drag force pushing the rotor.