Performance enhancement of IMC-PID controller design for stable and unstable second-order time delay processes针对稳定和不稳定二阶时滞过程的 IMC-PID 控制器的性能改进设计

An IMC-PID controller was proposed for unstable second-order time delay system which shows the characteristics of inverse response (RHP zero). A plot of Ms versus λ was suggested to calculate the suitable tuning parameter λ, which provides a trade-off between performance and robustness. Six different forms of process models were selected from literature to show the applicability of the present method. Performance of controller was calculated by ITAE and total variation TV and compared with recently published tuning rules. Undesirable overshoot was removed by using a set-point weighting parameter. Robustness was tested by introducing a perturbation into the various model parameters and closed-loop results show that the designed controller is robust in the case of model uncertainty. The proposed method shows an overall better closed-loop response as compared to other recently reported methods.