Set-point weight selection for robustly tuned PI/PID regulators for over damped processes

The aim of the paper is to present tuning equations for proportional integral (PI) and proportional integral derivative (PID) controllers with set-point weight (two degrees off freedom - 2DoF). These are based on a performance/robustness trade-off analysis with first- and second-order-plus-dead-time (FOPDT, SOPDT) models. On the basis of this analysis a tuning method was developed for 2DoF PI and PID controllers that allow designing closed-loop control systems with a specified M_S robustness that at the same time have the maximum IAE performance allowed. The control system robustness is adjusted varying only the controller proportional gain.