Optimal design on stator of cylinder-sphere 3-DOF ultrasonic motor using structural dynamics method

A new cylinder-sphere 3-DOF ultrasonic motor is developed through optimal design of its stator using a structural dynamics method and following the methods of our previous research on a multi-DOF ultrasonic motor. First, the stator structure is selected according to the design requirements of the stator and our experience. Second, a structural dynamics model for the stator is established by the FE method, which uses more accurate volume units. Third, design variables of the stator are determined by dynamic sensitivity analysis. Then, an optimal design model is constructed based on the FE method and the sensitivity analysis. Finally, the constrained variable metric (CVM) method is adopted for searching optimum parameters, and a new optimal design program for the stator is developed in the MATLAB environment. Experimental results show that the stator´s measured modal frequencies and mode shapes are consistent with the results obtained with the optimal design program that is time-economical.