Research On High Rotating Speed Ultrasonic Motors Utilizing Disk-like Stator’s Radial Vibration

With the rapid development of mechatronics,the advanced equipment tends to be highly integrated and miniaturized.Among them,piezoelectric actuators have the characteristics of simple and compact structure,high energy density and free from electromagnetic interference,which are very suitable for integration into micro-electromechanical systems.However,the high speed rotating ultrasonic motor developed in recent years is facing several vexing problems such as high driving voltage,complicated excitation mode and low energy density.Aiming at the above problems,this paper proposes a high-speed ultrasonic motor based on radial vibration of the disk,and explores a new method of low-voltage,simple structure and high-energy density piezoelectric drive.The main research contents and results are as follows:1.A dual-mode disc-type ultrasonic motor was designed and optimized,and a prototype was machined with a maximum no-load speed of 1350 rpm.2.For the problems existing in the dual-mode motor（difficult modal coupling and low no-load speed）,a single mode disc-type ultrasonic motor was designed,and the effects of different substrate materials on piezoelectric vibrators were compared.3.The single-mode disc-type ultrasonic motor was machined and assembled.Its weight is 3 g,the operating frequency band is from 85.3 k Hz to 85.5 k Hz,and the pre-spring pressure is 0.5 N.Under the driving voltage of 35 V_pp,the maximum no-load speed could reach 3000 rpm,the output torque was0.15 m N·m,and the output power was 47 W.4.Considering that the single-mode motor has the advantages of low driving voltage and high speed,it is considered to be the power source device of the micro aerocraft,and the rotor（3020 blade）speed experiment is carried out on it.The experiment shows that the principle prototype rotor can reach the maximum speed of 2300 rpm under the driving voltage of 40 V_pp.The experiments show that the single-mode disc-type ultrasonic motor has the advantages of simple mechanism,low drive voltage,high energy density and easy output control.