A Unified IMC based PI/PID Controller Tuning Approach for Time Delay Processes

This paper proposes a new PI/PID controller tuning method within filtered Smith predictor (FSP) configuration in order to deal with various types of time delay processes including stable, unstable and integrating delay dominant and slow dynamic processes. The proposed PI/PID controller is designed and tuned based on the IMC principle and a new constraint without requiring any approximation or model reduction techniques. To have an enhanced disturbance rejection for integrating processes, an improved IMC filter is adopted to design a PID controller. Meanwhile, the set-point weighting method plays a vital role in achieving satisfactory performance in both servo and regulatory problems. The trade-off between robustness and regularity performance is easily adjustable by tuning only one parameter. Simulation results corroborate the effectiveness of the proposed method based on different performance indices including IAE, total variation, overshoot and the maximum peak of error performance indices.