PID autotuning for weighted servo/regulation control operation

This paper analyzes optimal controller settings for controllers with One-Degree-of-Freedom (1-DoF) Proportional-Integral-Derivative (PID) structure. A new analysis is conducted from the point of view of the operating mode (either servo or regulation mode) of the control-loop and tuning mode of the controller. Performance of the optimal tuning settings can be degraded when the operating mode is different from that selected for tuning and obviously both situations can be present in any control system. In this context, a Weighted Performance Degradation index, that considers the importance and balance between the servo and regulation operation modes, is minimized and based on this minimization, an autotuning procedure as a function of the normalized process dead-time is proposed.