Optimal tuning rules for an absolutely stable nonlinear PI controller with a practical application

Tuning nonlinear controllers which can be easily implemented in real-time applications is a challenging task since stability in the controlled loop has to be guaranteed. In this work, a set of new tuning rules for nonlinear PI controllers applied to first-order plus dead time systems is presented. The design method guarantees the asymptotic stability of the control system while providing optimal performance. Moreover, the tuning rules offer good robustness in the presence of process variations and disturbance. This controller is easy to implement and the efficacy of the method is shown through various simulations. Furthermore, the real-time implementation of the tuning rule on a control loop for an airflow process is shown.