SELF-TUNING PI-PID REGULATORS FOR STABLE SYSTEMS WITH VARYING DELAY

A new self-tuning PI-PID regulator is presented, based on a fixed-structure simplified model of the process. To cope with the majority of real-size applications, the simplified mode is assumed to incorporate a variable or unknown time delay. Therefore, the core of the PI-PID regulator is an effective identification algorithm suitable for the on-line estimation of the unknown time delay in sampled systems. In the development, particular emphasis is given to all those aspects which make an algorithm really applicable in an industrial environment, such as start-up and initial tuning phase, choice of the sampling period, ease of the control synthesis criterion. Simulation experiments demonstrate the potential of the new regulator.