Parameters Tuning Of PID Controller And Its Application

PID(Proportional, Integral and Differential) controller is used widely in kinds of industry circumstance for its simple structure, easy implementation and strong robustness. And as an abroad control law, during a long period, PID control has not been knocked out from the emergence of different advanced arithmetics, and on the contrary, it plays an major role in sundries of control technologies.The tuned parameters of PID controller, whether excellent or not, are the precondition of good closed-loop control effects while it is used to application. So far, kinds of parameters tuning methods of PID controller have emerged in endlessly, which bring much energy for the study of PID controller. But, compared to classical tuning methods, these advanced tuning methods behave not so perfect as to be expected. And the result is mainly arose from the simple structure of PID controller which decide the limitation of control quality when used to application, and it also results in bad performance when it is used to long time delayed system and un-stable object. For the same reason, PID controller just determines few zero and pole points which also lead to not so good control quality of the closed loop. In addition, PID controller cannot satisfy the different performance requirement of set-point tracking and restrain outer disturbance at the same time.The paper expatiate the common-used classical parameters tuning methods of PID controller in detail, and some research work is done by MATLAB/SIMULINK toolbox. And two improved parameters tuning methods of PID controller are proposed in the paper aiming at minimum model. Mainly work and results are summed bellow:Based on the further study of Phase-Margin method for PID parameters tuning, a new more practical method is proposed and the corresponding formulas are given in this paper. The proposed method break the limitation of function between the phase margin and the relay's width, and can freely choose the coefficient of the delay according to different object characteristics, which leads to better quality of the surge and then give better control performance of the PID control system. And the new method also can bring to bear a wider application compared to the PM method.As for the difficulty to determine the point of maximum slope of the transition curve and the bug of using little information of the system, a PID parameters tuning method is presented in this paper based on multinomial fitting of the model's transition curve. The proposed method can cover the shortage of the traditional method and make the best of the transition cure information. So the method proposed can avoid repeated experiments and do the research work of parameters tuning of PID controller economically with timeand effort. Additionally, the method is easy to be implemented by computer programming and has a certain usefulness.The summary of the paper and personal perspective are given in the end of the paper.