Modeling and performance evaluation of 2DOF spherical traveling-wave type ultrasonic motor

The objective of our research is to investigate the performance evaluation of traveling-wave ultrasonic motor with two-degree of freedom (2DOF-USM). The space structure of 2DOF-USM is introduced briefly. The mathematic model of the motor is established based on friction drive mechanism. Through relation of space location, calculating the driving force and friction force at arbitrary point of contact area, the analytical expressions of the mechanical characteristics are deduced. The influence of model parameter on motor characteristics is presented through simulation. The validity of the model is verified by means of comparing the simulation results and the experimental ones. This article lays a theoretical foundation for spherical traveling-wave type ultrasonic motor’s well performance and trajectory control next step. The maximum output torque of developed motor reaches 0.10N·m, the maximum speed is 90rpm.