Time-optimal Plug&Control for integrating and FOPDT processes

The plug&control feature (i.e. to automatically make the controller work properly after simplyconnecting it in the control architecture, without further intervention from the operator) is desired in industrial regulators in order to minimize the tuning effort from the user and in order to speed up the startup of the controller. In this context, a new strategyfor plug&control is proposed for integrating and first order plus dead time (FOPDT) processes. It is based on the use of three-state and PID control, and on the use of a simple least-squares based identification technique. The main advantage of the methodologyis that it is time-optimal, i.e. the process output attains the desired set-point value in minimum time, subject to the saturation limits of the actuator. Simulation results are given to show the effectiveness of the method.