Research On Driving And Control Device Of Ultrasonic Motor Holding Invariable Working State

Ultrasonic motor has been applied in many areas for its particular advantages. However, the operational states of ultrasonic motor are affected easily by the external factors which hinder the further promotion of ultrasonic motor application. Driving and control techniques are important for applications of ultrasonic motor. Although, the domestic existing closed-loop ultrasonic motor drive controller use many different kinds feedback signals to control the motor. The tracking control indicator is limited to the motor speed, rather than their working states. According to a Japanese patent and some results of experiments, we can remain the state of the ultrasonic motor by keeping some phase difference which exists in motor, even motor-driven conditions changing, such as keeping the motor running in the most efficient state. Experimental research indicates that there are some phase differences may reflect the variety of the motor state. But the phase difference between the drive voltage and the monitor electrode voltage is much more appropriate to be exploited for its big band width and being detected easily. In this paper, the stability of the phase difference method is used to achieve stability in the state of the ultrasonic motor.The following are the chief research achievements and work of this thesis.First, the hardware is introduced in detail, such as the components of drive and control system, block diagram of the system architecture design, design programs, the working principle of functional modules and circuit implementation. Experiments are used to support the design.Next, classic PID control algorithm which is more simple and operable is used to be the software control method because the subject is concerned a preliminary exploration. We also introduce the classification of PID control algorithm, the principle of incremental PID control strategy and control flow chart. At last practical software is achieved according to requirement and the hardware.At last, we study the self-developed drive controller through a serious of experiments on motors. After online debugging experiment, we discover and resolve some problems. And an excellent ultrasonic motor drive controller is designed finally. Some results of the experiments by using the new drive controller are given.