Simulation and experimental study on elastic fin ultrasonic motor

In order to understand motor operation, a simple simulation model has been developed. This simulation model is based on a fundamental vibration mode of a cantilever for modeling elastic fins which are planted on a rotor slightly leaned from normal. At the free end of the fins, friction is taken into account. The frictional force is assumed to be proportional to a dynamic normal compression force. The vibrator, the fins, and the rotor are modeled with a simple lumped element equivalent circuit. The simulation model includes these linear elements and nonlinear elements which indicate the behavior of the friction force and the unidirection of force between the rotor and the stator. This equivalent circuit is simulated with the time-domain backward difference method. It is found that, at proper operating conditions, the fin tips maintain contact with the stator, and no backward slip occurs