Mass transfer from the rotor to the stator for improving the speed of the piezoelectric motor based on centrifugal force.

To improve the speed of a piezoelectric motor based on centrifugal force, a method is proposed on the basis of mass transfer from the rotor to the stator. Multi-degree-of-freedom vibration models are established before and after mass transfer. A mass of 150 g is transferred from the six-hole rotor to the stator. This process increases the rotation frequency of the rotor under the same friction loss and increases the energy fed into the rotor by the stator. The motor operates at a frequency close to the resonance frequency. The change in the initial phase with the operating frequency close to the resonance frequency is analyzed, and the phase adjustment device and the signal processing circuit are designed. Two prototypes, one with and one without mass transfer, are fabricated and measured. As the initial phase is adjusted from 0° to 75°, the motor rotation frequency gradually increases, approaching the resonant frequency of the motor. When the excitation voltage is 790 Vp-p, the speed of the piezoelectric motor with a mass transfer of 150 g reaches 11 004 rpm, which is 89% faster than the speed of that without mass transfer.