Study And Design Of Controller Based On The Immune Principal

Artificial immune system(AIS),an emerging intelligent method,is a calculation model designed on the basis of biological immune system's functions, features and mechanisms.With sound performance in study,recognition, memorization and character extraction,it can solve many complex problems that are difficult for traditional algorithms.Therefore,AIS has become a research focus in recent years and has been widely applied in many fields.This paper mainly discusses AIS's application in automatic control field. Immune controller blocks are established according to existing immune network models and then a motor speed regulation system is adopted as the control object for simulation in Matlab.Another intelligent control theory is introduced in the parameter optimization of immune controller to yield a complementary result. The major content and achievements of this paper can be summarized as the follows:Firstly,the history and status quo of AIS and concerning concepts of biological immune system are introduced and special attention is given to the principal and application research of AIS.Secondly,network models such as immune adjusting control,double-factor control and Varela immune control are analyzed and according to which corresponding controllers are established.Simulation researches are conducted to verify the performance of each controller and to analyze the parameter characteristics.One of the immune controllers is chosen to draw a comparison with traditional PID controller in the aspects of dynamic response,robustness and delay resistance.Simulation results demonstrate that immune controller enjoys some unique advantages compared with PID controller.At last,three improvements are made to the classic immune control method. Firstly,Hill function is chosen to imitate the nonlinear relationship between helper T-cell and antigen in place of the original linear relationship;then the immune adjusting control and integral part are weighted before output to avoid overshoot;and at last fuzzy control theory is adopted to approximate the nonlinear function used in immune adjusting controller in place of the original fixed function to establish a fuzzy immune controller.Simulation results show that this controller could yield better performance in dynamic response, robustness and anti-interference than both immune controller and fuzzy controller.