Resonance Suppression and Controller Design of Electric Servo Mechanism Based on Notch Filter

In view of the mechanical resonance existing in electric servo mechanisms, which affects the system bandwidth and steady-state accuracy, a dual-T notch filter with adjustable depth and width is proposed for compensation, and the design method of notch filter is given. For the system compensated by the notch filter, a PID controller is used to correct it into a Type II system. A method for tuning controller parameters with maximum phase margin is presented, which ensures system stability margin while maximizing the open-loop cutoff frequency and gain in the low frequency band, thereby improving the system's bandwidth and steady-state accuracy. Finally, a system simulation model was built in the Matlab/Simulink environment. The simulation results show that the introduction of notch filter can effectively eliminate the persistent oscillation in the steady state of the system. The system has good steady-state and dynamic performance, and has good tracking accuracy for continuous changing signals, which demonstrates the effectiveness of the method proposed in this paper.