Modeling and experimental validation of a linear ultrasonic motor considering rough surface contact

Linear ultrasonic motor is driven by the interface friction between the stator and the slider. The performance of the motor is significantly affected by the contact state between the stator and slider which depends considerably on the morphology of the contact interface. A novel fiction model is developed to evaluate the output characteristics of a linear ultrasonic motor. The proposed model, where the roughness and plastic deformation of contact surfaces are considered, differs from the previous spring model. Based on the developed model, the effects of surface roughness parameters on motor performance are investigated. The behavior of the force transmission between the stator and the slider is studied to understand the driving mechanism. Furthermore, a comparison between the proposed model and the spring model is made. An experiment is designed to verify the feasibility and effectiveness of this proposed model by comparing the simulation results with the measured one. The results show that the proposed model is more accurate than the spring model. These discussions will be very useful for the improvement of control and the optimal design of linear ultrasonic motor.