Study On Compound Control Of Unstable Time Delay Systems

In the field of industrial control,time delay is common.Many of the controlled objects have the characteristics of pure lag.Because of the existence of time delay,the controlled variables of the system can not reflect the changes of system error and disturbance in time.The measurement signal in the system will be passed to the controller for a period of time,which will cause the system to overshoot,the adjustment time will increase,and the stability of the system will be greatly reduced.Therefore,the time-delay system is very difficult to control,and the longer the lag takes up the whole dynamic process,the harder the system is.Therefore,the problem of time-delay system control has been puzzled by many scholars at home and abroad.Especially for unstable time-delay systems,many control methods do not work because such objects have the poles of the right half complex plane.With the increasing complexity of industrial control systems,unstable time-delay systems are also common,such as temperature control system,water turbine generator set speed control system,chemical plant polymerization control system,helicopter pitch control system,and so on.Therefore,the study of this problem is of great practical significance.In this paper,we study the optimal control for such a time-delay controlled object.For the unstable time-delay systems,based on the time-delay abstract model,the problem of the unstable time-delay system is transformed into a time-delay system by using the method of pole assignment.Using the two optimal control algorithm,the first optimization is used to approximate the infinite dimensional factor in the control system with the finite dimensional approximate mathematical model,and the first optimal control is carried out by using the ITAE optimal criterion.Back to the infinite dimensional space,we study the infinite dimensional controller and so on,and complete the second optimization.Finally,a single capacity unstable and integral unstable time delay system is simulated and verified.Finally,in the actual project,for the unstable time delay system temperature control system,the characteristic model control algorithm and the two optimal ITAE optimization control law are combined.The simulation results verify the effectiveness of the proposed method and improve the dynamic performance of the system.