Fuzzy-PID Control Of External Disturbance Vibration For Active Magnetic Bearing

Active magnetic bearing has the superior performance, such as no friction, no wear, long service life, no pollution, high speed and high precision. Since the rotation precision and stability of the active magnetic bearing are critical, it is of great significance to maintain the stability at the equilibrium position of the active magnetic bearing rotor under dynamic loads or external disturbance.Based on the research result of active magnetic bearing, the mathematical model of the active magnetic bearing is established. The parameter self-turning fuzzy-PID controller is employed and simulation is carried out. The fuzzy-PID control algorithm is implemented in DSP and is verified through experiments. The contents and conclusions of this paper are summarized as follows:(1) The mathematical model of a four degrees of freedom active magnetic bearing is established, decoupling condition is anglicized, and decentralized control scheme in control of magnetic bearing is used. Experiment result shows that the traditional PID control has good control effect when the external disturbance is small.(2) The parameter self-tuning strategy of fuzzy-PID control is employed to solve the vibrations caused by external disturbance. According to the rotor’s different state, fuzzy rules in accordance with the experimental rig are designed, and the parameter self-turning fuzzy PID control is applied in this thesis to achieve the rotor online self adjustment. Using the Matlab/Simulink software, simulation concerning the actual suspension of the magnetic bearing rotor, anti-disturbance and the loading condition are conducted, it is verified that the fuzzy-PID control is much better than the traditional PID control in terms of anti-disturbance and responding to dynamic loads.(3) The fuzzy-PID control algorithm is implemented in DSP and controller’s performance is verified through experiment which includes experiments of stationary rotor suspension, rotation under load and withstanding large impact disturbance. Experimental data analysis shows that the performance of fuzzy PID control is improved compared with traditional PID control, with better anti-disturbance and self-adaptability.The above contents and conclusions can provide reference for industrial application of active magnetic bearing system.