Kinetic model of Three Degree-of-Freedom traveling wave type ultrasonic motor

Three Degree-of-Freedom (3DOF) traveling wave type ultrasonic motor (USM) can move at three degrees. The principle and basic structure of 3DOF traveling-wave type USM are presented in this paper firstly. Then through coordinate conversion the distribution of the force on the contact area of rotor and stators can be obtained when the rotor rotates. Thus the motorpsilas driving and friction force can be calculated on the contact area. Also the driving and friction torque can be derived. By solving the equations of torque balance and force balance of stator the motorpsilas kinetic model can be deduced. By simulation structure parameters and stator velocity are analyzed and the model can be verified preliminarily.