Study of a hollow ultrasonic rotary motor

In this study, a hollow cylinder ultrasonic motor has been designed in order to be integrated into mechatronic devices where the bore is either occupied for functional reasons or must remain free. The design approach consists in performing a FE modelling of the motor structure. After finding the different vibration modes, it is possible to find out the axial and tangential deformation amplitudes of the resonator allowing the motor rotation when a pre-stressing force is applied to the rotor. Using an optimisation methodology based on a sensitivity analysis using in particular the design of experiments method and then a FE optimisation, it is possible to maximize the deformation amplitudes in both directions to obtain higher torque and speed of the motor. Along with this process, functional models are built in order to validate the adopted design methodology and verify if the chosen motor concept is appropriate.