A High Robustness Of The Smith-pid Parameters Tuning

In this paper, a systematic and comprehensive study of the Smith predictor has been conducted. As to the weak performance of Smith predictor when model-mismatch or interference happened, this paper states a Smith-PID tuning rule for the FOPDT and SOPDT while a practical PU) form was used. Insight into the design process is gained by viewing the Smith predictor from the perspective of internal model control. The tuning rule gives the following result: Firstly, there is only one tuning parameter A in the tuning rule which is directly related to robust perfonnance and can be calculated from formulae. Secondly, for the controlled objects with varying parameters or interference, the tuning rule results high robustness. Thirdly, comparing the Smith-PD tuning rule with the Ziegler-Nichols, Refined Ziegler-Nichols and 15Th tuning rules, a significant improvement of closed-loop performance and robustness to model-mismatch and interference is obtained. The results show that the Smith-PID controller using the tuning rule can be used as foundational sub-system in the distributed control system (DCS).