The Study On The Drive And Control System Of Traveling Wave Ultrasonic Motor Based On Neural Network

Ultrasonic motor's vibration is excited by the conversely piezoelectric effect of piezoelectric materials. With the friction coupling, the rotation of the rotor or moving of the slider is generated. As a direct driving motor, it is becoming a hotspot in the field of mechanical and electrical control. In this paper, A farther study and design on drive and control of USM is made. According to USM's characteristic and it's driving theory, a new kind of USM's drive and control circuit is designed, it is used to realize frequency tracking and drive USM, an algorithm using BP neural network is selected for the system. This system is implemented on a DSP because the DSP is accuracy and efficient. On basis of referring and analyzing a large quantity of literatures, the following work has been carried out.The application of BP neural network to speed control system on USM is discussed, and a program is designed for training the BP neural network by Matlab's nntool, a three layers neural network of 2-8-1 is determined through simulation, then write the weights and biases of the NN into DSP to make on-line training, and it reaches the purpose of controlling USM's speed.Because of the temperature rising of ultrasonic motors, load changes, and vicinal surrounding changes and so on, the resonant frequency will shift, leading to working stability drop. A new kind of driving circuit is designed, it realizes driving and frequency tracking of USM. The proposed driving circuit includes a low-pass filter circuit,feedback circuit,signal generated circuit,phase shifted circuit and power inverter circuit.A TI cooperation's DSP(TMS320LF2407A) is chosen for the drive and control system based on the characteristics of USM, the interface circuit,each function's flow chart and algorithm program are designed. The program of whole control system is testing on the plat of CCS. A USM drive and control system based on DSP is designed, the results show that the instrument is efficient and accurate, and run stably, so it can realize drive and control of USM better.