Composite control method of DC motor based on speed feedback

Abstract

In view of problems of slow response speed and bad anti-disturbance ability existed in traditional control system of DC motor, the paper proposed a composite double-loop control method of DC motor based on disturbance observer and speed observer. The method adds feed-forward control, disturbance observer and speed observer in PID control of DC motor. The feed-forward control is used to improve response speed and tracking performance of the system. The disturbance observer makes external torque disturbance and output difference between practical object and nominal model caused by parameters change of motor model to be equivalent to control input end, namely observes equivalent disturbance and equivalent compensation is introduced in control, so as to realize complete inhibition for disturbance. The speed observer takes torque command and practical speed of the system as inputs, deploys observing and filtering functions to get observing speed without high-frequency components and lagging behind practical speed of the motor to replace the practical speed, the observing speed is used as feedback signal of speed. Simulation result shows that the method has good robust and reduces vibration phenomena and tracking error of speed and position of the motor caused by measuring noises.

Keywords

• dc motor
• double-loop control
• composite control
• high-frequency noise
• disturbance observer
• speed observer
• pid control