Torque for non-contact piezoelectric motor modulated by electromagnetic force

In this paper, the structural design and driving mechanism of a non-contact piezoelectric motor modulated by electromagnetic force are introduced. The equations of the electromagnetic force and torque of the electromagnetic modulation mechanism for the motor are deduced. Based on the piezoelectric constitutive equation and torque balance equations of the driving system, the equation of the piezoelectric driving torque is also obtained. Using these equations, the influences of the related parameters on the relationship between electromagnetic torque and angle difference between pole and rotor are studied. The influences of the main parameters and signal frequency on piezoelectric driving torques are analyzed. Based on them, the torque optimization of the motor is completed and the load-carrying ability of the motor is increased by about 50 times. A prototype of the motor is developed. Its output torque is tested and compared with calculated one which illustrates the theoretical model here.