Improving the efficiency of a hollow ultrasonic motor by optimizing the stator's effective electromechanical coupling coefficient

Abstract

For application in control moment gyros, we considered a hollow traveling wave ultrasonic motor with a diameter of 70 mm. The effective electromechanical coupling coefficient (EMCC) of the stator was determined. The influence of the vibration mode of the stator and the structural dimensions of the metal elastomer and piezoelectric ceramic ring on the effective EMCC was investigated. According to the FEM simulation results, four different stators were manufactured and tested. The EMCC obtained through the simulations was greater than the measured values, with the lowest simulated and measured values being 17.202% and 16.431%, respectively, and the highest simulated and measured values being 28.452% and 26.780%, respectively. The relative errors between the simulated and measured values were all less than 10%. This work will help us to improve the output efficiency of the motor.