Robustness/performance tradeoff for anisochronic plants with two degrees of freedom PID controllers

In this paper, the anisochronic model (which is able to represent both over-damped and under-damped process with the same topology) is used for the tuning of PI and PID controllers. The relationship between robustness and performance is analyzed for a wide range of model parameters and a tuning procedure is proposed. Then, the performance of the PID controller tuned with the anisochronic model is compared with other tuning methods. It was found that, not only the anisochronic model is well suited for robust tuning of the controller, but it is able to give better performance than other tuning rules, specially if the plant has high order.