Control scheme for multiple-input-multiple-output processes with time delays

Multiple-input-multiple-output (MIMO) processes with time delays commonly appear in chemical industry. Based on unity feedback closed-loop control structure, and combined with the characteristics of strong robustness of the two-degree-of-freedom (2-DOF) PID in terms of the Desired Dynamic Equation (DDE) method, a PI/PID decoupling controller was designed through setting a static decoupling controller on the input of the controlled process. The controller can not only achieve a significant decoupling among the responses of each output of the nominal system, but also realize the online tuning of adjustable parameters. Comparing with the deficiency of numerical calculation method, the design is simple and widely applied. Finally, some simulation examples are supplied to demonstrate the superiority of the proposed method.