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

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