Study On Neural Network Inverse And Analytic Inverse Speed Control Of Ultrasonic Motor

From the appearance time of Ultrasonic motor to now, the study of it has beenreceived more attention especially for the structure, the operation mechanism and themanufacturing technology. With the research going on, how to drive and controlultrasonic motor in order to give full play to its performance has become an importantpart of the research of ultrasonic motor. Ultrasonic motor is not easy to control becauseof the significant time-varying, nonlinear characteristics existed in the operation of theultrasonic motor. A method named inverse control is designed that based on neuralnetwork and analysis inverse to realize the effective speed control of ultrasonic motor.Neural network inverse control is based on the neural network inverse model ofUltrasonic motor driver system. The neural network inverse model of Ultrasonic motoris built. The process is as follows. First, this paper designs a model structure based onthe experimental data, which is a three layer nonlinear time delay network model. Andthen, identifies Series-parallel neural network. At last, establishes the neural networkinverse model of the ultrasonic motor, whose input and output are the speed of motorand the driving frequency. The input-output mapping relations of the model areapproximate to the measured data, and this proves the effectiveness of the model.Pseudo linear system is constructed that composed of inverse model and ultrasonicmotor by applying the neural network inverse model. Considering the time-varyingcharacteristics of ultrasonic motor, the additional controller is designed based on inversecontrol theory, and which forms the closed-loop neural network inverse controller ofultrasonic motor.On the other hand, the inverse model of ultrasonic motor driving system, which isobtained by analytical method based on the variable parameters dynamic model of theultrasonic motor, and original system constitute Integral quadratic pseudo linear system. analytical inverse control method of ultrasonic motor is presented lately. Theexperiments of speed control confirm the effectiveness of the above control methods.