Control design for ultrasonic motors with dynamic friction interface

Abstract The paper studies the control design of a piezoelectric actuator. Ultrasonic motor is one example of a friction-driven system, for which the transfer of power between the actuator (vibrator) and the system to be controlled (slider) is done via a friction interface. The paper introduces the recently developed LuGre friction model that include most of the desired friction characteristics (stick-slip, Stribeck, Coulomb, viscous and other hysteretic friction effects) [1]. This model describes the lumped effect of frictional contact. We also propose control laws that allows for a velocity control of such a mechanisms.