Two degree-of-freedom internal model control for first oder open-loop unstable processes with time delay

A two-degree-of-freedom control structure is used for chemical and industrial process with unstable pole and time delay based on modified internal model control. At first, a feedback proportional controller is applied to meet the objective of stable generalized second order plus delay time with overdamp. And then, the tracking controller is designed by the inverse of the model and the performance evaluation, two-step method is used to design the controller load disturbance rejection. The setpoint response and the disturbance response are completely decoupled, at the same time, the both of controller parameters can be adjusted independently to achieve the satisfying control effect. At last, simulation examples show the robust sability and the effectiveness of the control scheme.