High-efficiency piezoelectric motor combining continuous rotation with precise control over angular positioning

The letter describes a piezoelectric motor that combines the merits of piez oelectric materials, such as high power density generated at electromechani cal resonance, and a precise control of displacement. The motor utilizes a direct coupling mechanism between the stator and rotor, where a clutch driv es the rotor via locking it. The direct coupling makes it possible to trans mit the whole power generated in the piezoelectric element to the rotor, an d thus achieve the high efficiency of the motor. It also allows the combini ng of two regimes of operation: continuous rotation and a stepwise motion w ithin a 360 degrees interval with a high resolution of angular displacement . (C) 1999 American Institute of Physics. [S0003-6951(99)03232-5].