PI and PID auto-tuning procedure based on simplified single parameter optimization

In this paper a new auto-tuning algorithm for PI and PID controllers based on relay experiments is proposed to minimize the load disturbance integral error (IE) by maximizing the integral gain, subject to a desired phase margin, and a minimum required gain margin constraint. The main advantage of the proposed auto-tuning algorithm with respect to previous works is that it leads, for most of the processes, to PID tuning with close loop performance similar to PID designed using off-line numerical optimization. Moreover the algorithm is applicable to any linear model structure, including dead time and non-minimum phase systems.

► Auto-tuning algorithm for PI/PID to minimize the load disturbance integral error (IE).
► Relay experiments to obtain a line approximation of the system frequency response.
► Tuning of PI/PID with guaranteed minimum gain and phase margins.
► IE similar to the one obtained using full model off-line numerical optimization.
► Auto-tuning algorithm applicable to systems with dead time and non-minimum phase.