Robust IMC-PID Controller Design With Unstable Pole Process

With the development of industry,in the actual industrial process control system,there are many industrial systems of the process model which there are unstable poles.Due to the existence of these unstable zeros or poles,the stability of the system will be strongly affected,its dynamic performance and robust performance will also be affected.The controller design method and its parameter setting for the unstable process model are becoming more important control technology.Aiming at the first order unstable time delay process model(FOUPDT)and the second order unstable time delay process model(SOUPDT),this paper adopts the design method of double closed loop.The inner loop uses the proportional controller in the PID controller to stabilize the system process model and the nominal model.The IMC-PID controller is designed for the outer loop.In the process of parameter setting,the system dynamic performance index IAE is used as the objective function and the maximum sensitivity function of the robustness index M,as the constraint condition.Through the above parameter setting step,the dynamic performance and robustness of the system can be taken into account at the same time.Through the above operation the internal model controller set parameter ? can be set out,then we can get the Corresponding PID parameters of the three parameters to complete the controller parameter tuning.And then consider the existence of model error model that is the case of mismatch.In this paper,the post-stabilized process model is transformed into a standard closed-loop control model structure.Then,through the Rouse criterion,we can find the condition of the three parameters of the process model,the time constant and the delay constant to make system maintains the condition of robust stability.Finally,the effectiveness and superiority of the controller designed in this paper are verified by comparison with other scholars.