Open-loop step response IMC-based tuning of PIDA controllers

In this paper, we propose a tuning procedure for Proportional-Integral-Derivative-Acceleration (PIDA) controllers. In particular, starting from a third-order-plus-dead-time process transfer function estimated by evaluating an open-loop step response, the controller is tuned by means of an Internal Model Control (IMC) approach where the controller transfer function is reduced by truncating its Maclaurin series. Measurement noise is mitigated through the design of appropriate low-pass filters. A comparison with a previously devised open-loop Haalman tuning method based on pole-zero cancellation and with a similar tuning technique for a PID controller is performed. Further, experimental results with a temperature control laboratory are shown, demonstrating the practical applicability of these controllers in process control contexts.