Dynamic Contact Modelling for Resonant Piezoelectric Motors

Abstract:
Resonant piezoelectric motors use ultrasonic oscillating mechanical frictions in order to build up torque. One of the main difficulties in the modelling of a resonant motor dwells within the high nonlinearity of the stator/rotor contact boundary conditions. In this paper, we introduce a new way to simulate the contact for a piezoelectric resonant motor. This modelling approach has the advantage of tracking the resonance frequency evolution with contact parameters (pre-compression, surface roughness ...) with relatively short computation time. In order to validate the modelling results, the first chapter is dedicated to the experimental setup. We use a Langevin transducer as the vibrating part. It is placed in contact with a metallic disc as the passive part. The measurement variable is the admittance of the system. The measurement is performed with respect to the precompression force close to resonance and for low voltage supply amplitude. In the second chapter, we show the implementation of the modelling approach. We consider that at the contact interface, the stator/rotor interaction is represented by a spring. The value of the spring stiffness is computed while taking into consideration the roughness topography of the contact surfaces. A modelling/experimental results comparison shows a great deal of conformity