The Application Research Of Multivariable System Based On LTR Control Method

The control of multivariable systems in the industrial process,especially the control of complex systems is becoming the current research hot.When the traditional control method is expanded from single variable single delay systems to multivariable time-delay complex systems,the traditional method has poor robust stability,which can't acquire satisfied control effect.The Loop Transfer Recovery is an advanced control method,the requirement of systems can be met by designing the objective loop,and the closed loop control systems can realize satisfied robustness by LTR method.To achieve the LTR control structure with excellent performance,LTR control method is utilized for multivariable systems in this paper,which can eliminate harmful effects of time-delay and non-minimum phase terms.For multivariable systems with complex terms,corresponding LTR control structure is designed.The research of LTR control method has certain theoretical significance and practical value.When the external disturbances are added into the systems,the sensitivity function is introduced in this paper,and the disturbance rejection ability of LTR multivariable systems is demonstrated by calculating the sensitivity function of closed loop control systems.When the parameter uncertainty and model uncertainty are added into the systems,in this paper the Structured Singular Value analysis method is used to analyse the robust stability and robust performance,and the robustness of the control systems can be validated by the curve of SSV.As the traditional single freedom degree controller based on output error can't realize the control effect and robustness simultaneously,LTR method is used to design two freedom degree controller systems on the basis of LQG/LTR control structure.The front control term is designed to expand the systems,which constructs the two freedom degree controller with state feedback controller together.Utilizing the separation principle to design the controller and observer with independence.After calculating the gain matrix of Kalman filter,the state observer is built and LTR multivariable system is constructed.LTR control method is applied into the multivariable multiple-delay systems in this paper.After approximating the time-delay term,the LTR control structure designed by the approximated model is applied into the multivariable time-delay process object.Classical Industrial-scale Polymerization Rector and Wood-Berry model are simulated in this paper,and the results show that LTR control method has strong output response ability,good disturbance rejection ability and excellent robustness.The non-minimum phase multivariable system is decomposed into minimum phase part and all pass part,and the state vectors and state-space matrices are expanded to design the control system.The simulation of Jerome-Ray process indicates that the non-minimum phase LTR control system has satisified control effect and strong robust performance.