Force transmission model of a cylindrical linear ultrasonic motor

A force transmission model of a cylindrical linear ultrasonic motor, which uses the longitudinal and the bending hybrid vibration modes, is established in this paper. The analytical model is used for the guidance about the design of the interface and the analyses about the influence of the preload and interface on the motor´s performance. Hertz contact and Coulomb friction are used in the analysis of kinetics. The interface friction material is modeled by normal linear spring and tangential linear spring. Based on momentum conservation in normal direction, the paper deduces the relation among the contact position of the stator and the slider, the preload and the interface friction material physical parameters. Based on the relationship between the longitudinal vibration velocity of the stator and the speed of the slider, the contact is divided into stick instance and slip instance. The tangential thrust of the stator is deduced. The simulations are performed, and the results are validated by experiments.