Modified Smith predictor and controller for time delay processes

A modified Smith predictor control scheme is proposed for controlling stable, integrating and unstable processes with time delay. The two-degrees-of-freedom control structure along with simple tuning rules result in improved servo and regulatory performances by independently tuning a single control parameter. A convenient property of the proposed control scheme is that it decouples the setpoint response from the load response. The H₂ optimal control method is used to design the setpoint tracking controller and an optimal IMC filter is proposed to design a PID controller that produces good disturbance rejection performances. Simulation results show the simplicity and superiority of the proposed method compared with some reported methods.