Optimal design of a rod shape ultrasonic motor using sequential quadratic programming and finite element method

Many design requirements need to be considered in designing an ultrasonic motor. To solve the multi-objective optimization problem, sequential quadratic programming and finite element method are applied to the design process. The finite element method is used for modal analysis and harmonic response analysis of the ultrasonic motor. The sequential quadratic programming is employed to determine the optimal design solution. To validate the effectiveness of the proposed method, it is applied to the optimization of a rod shape ultrasonic motor. Design results show that all the requirements of motor design are satisfied and the design indexes related to motor performance show significant improvements after optimization. A prototype motor with 15 mm in diameter is manufactured using the optimization results. The stator vibration characteristics and the motor performance are tested. The results show that this design method is available and effective for the design of ultrasonic motors.