Desired Characteristic Equation Based PID Controller Tuning for Lag-Dominating Processes With Real-Time Realization on Level Control System

Objective of this study is to design proportional-integral-derivative (PID) controller with cascaded lag filter based on desired characteristic equation for lag-dominating processes. Here, attempt is made to formulate the closed-loop characteristic equation which comprises of multiple poles placed at the desired locations. Moreover, a guideline is also provided to choose the parameters of the closed-loop characteristic equation based on optimal values for performance and robustness indices. Efficacy of the proposed scheme is verified through simulation study with first-order plus dead time (FOPDT), second-order plus dead time (SOPDT), and pure integrating plus dead time (IPDT) processes in comparison with recently reported PID tuning relations. Robustness of the proposed controller is also tested in presence of perturbation for process model parameters. In addition, Kharitonov's interval polynomial is used for robust stability analysis. Real-time experimentation is also performed on a level control loop.