The performance analysis and system optimization of the composite position control system of DC motor

During the design process of composite positioning control system(CPCS) for the DC motor,it was found that the dynamic response curves for the motor speed etc.were oscillated,and they showed a certain degree of instability.In order to explore the correlation between the oscillation and the internal structure of the CPCS,we analyzed and compared the dynamic response curves,the root locus maps,and the frequency characteristics on MATLAB.The result shows that by using the reduced-order method,the transferring function of the high-order control system can be simplified as a basic form of a real zero,a real pole and two pairs of complex conjugate poles.The root cause of the oscillation and the stability reduction of the CPCS system is the removal of the pair of complex conjugate poles that are closer to the origin.By increasing the real part or decreasing the imaginary part of another pair of complex conjugate poles,the system oscillation can be reduced or eliminated.This conclusion has important reference value of improving the control system's positioning accuracy and stability.