Design and finite element analysis of a novel longitudinal-torsional hybrid ultrasonic motor

This paper reported an ultrasonic motor using the 1st longitudinal and the 2nd torsional (L-T) modes. The stator slots were useful to tune the resonance frequencies and increased L-T displacements largely. By cutting slots, which determined the number of oscillators, the whole stator was changed into independent vibrators. The more independent vibrators, the bigger power it outputs. The stator possessing different number of vibrators can realize frequency tuning by increasing outer diameter. Piezoelectric elements were pasted on the outer surface of the metal substrate. L-T hybrid vibrations of the driving surface can be excited when suitable electrical signals were applied to piezoelectric units. The working principle of the designed motor was analyzed particularly. The optimal slots dimension and location, including vibration characteristics can be obtained using the finite element analysis software, ANSYS. The analyzed results and experiments verified the proposed motor possessing good performance.