Development of a novel single-mode miniature standing wave ultrasonic motor

A novel single-mode miniature standing wave ultrasonic motor (SUSM) is proposed. The SUSM uses the first extension vibration mode and second extension vibration mode of the stator to generate different diagonal vibration trajectories and drive the rotor to rotate in different directions through a single-phase signal. The bidirectional motion of the SUSM can be realised by switching the two vibration modes and excitation methods. The motor is designed and the operating principle is analysed. The resonant frequencies of the two vibration modes are determined by the finite element simulated analysis, and the transient analysis is adopted to obtain the diagonal trajectories of the driving part. Finally, a prototype of the single-mode SUSM is developed and the mechanical performance of the prototype is measured and evaluated. According to the experimental results, the motor has a no-load speed of 265.37 rpm (B1 mode) and 320.20 rpm (B2 mode) in each direction under 200 Vp-p and 100 Vp-p voltage excitation, and the maximum load is 60 mN and 70 mN, respectively.