The Pid Controller Parameter Tuning And Its Stability Region

PID (Proportional, Integral and Differential) controller is used widely in kinds ofIndustry circumstance for its simple structure, easy strong robusmess and implementation.And as an abroad control law, during along period, PID control has not been knocked outfrom the emergence of different advanced arithmetics, and on the contrary, it plays anmajor role in sundries of control technologies.Whether the PID controller can keep the control performance good is due to thetuning of the PID parameter. With the development of computer technology and artificialintelligence in automatic control field, auto-tuning PID controllers began to be used inrecent years. These methods have brought the energy for the research of the tuning of PIDparameter.The stability of the closed-loop system is first considered in controller design. If thesystem is not stable, it is not benefit to improve other performances. Based on the aboveproblems, the main research ideas and results obtained in this paper are as following.Firstly, the paper introduces the developing process and the brief introduction of PIDcontrollers. Against some the weaknesses of Conventional PID controllers, we proposeimproving measures-by nonlinear PID controllers, and introduce several designingmethods of nonlinear PID controllers. The results of Simulation show that the nonlinearPID controller advantages. We also summarize the research situation on the tuning of PIDparameter, highlight the basic and improved methods based auto-tuning relay-PIDcontrollers, and give examples of the simulation. At last, for the high-step system, by themultinomial Hermite-Biehler generalized theorem, a new method is introduced, whichcould determine the stability region of PID parameter in the closed-loop system.