Parameters identification and contact analysis of traveling wave ultrasonic motor based on measured force and feedback voltage

•A novel model and measurement method for contact analysis of TWUSM are proposed.•The proposed measurement method make it possible to determine motor parameters in running TWUSM.•Vibration parameters in our model are identified based on measured force and feedback voltage rather than theoretical assumption.•The simultaneous effects of the preload force on the resonance frequencies and vibration amplitudes were validated rather than one effect.•Some phenomena, such as the variations of starting-up voltages and working ranges can be predicted and analyzed.•Very useful and convenient for the motor design, performance prediction, working range choice and control of TWUSM. In previous studies, contact models of traveling-wave ultrasonic motor (TWUSM) only considered the effect of the preload on the resonance frequency, and were based on theoretical calculations or assumptions because vibration parameters in working conditions are hard to measure. In this paper, a novel model and measurement method for contact analysis of TWUSM are proposed. The proposed measurement method enables the determination of vibration parameters during motor operation. Our model differs from previous reported models in three aspects: vibration parameters are identified based on measured force and feedback voltage rather than theoretical assumptions; the simultaneous effects of the preload force on the resonance frequency and vibration amplitude were analyzed and validated; some phenomena in working conditions, such as the starting-up voltages and working ranges under different preload forces, can be predicted and analyzed. The feasibility and effectiveness of this model was verified by the good agreement between the measured and calculated results. Our work provides a very useful and convenient way for performance prediction, working range choice and control of TWUSM.