Closed-loop evaluation and PI controller redesign satisfying classical robustness measures

In this paper it is proposed a procedure for closed-loop evaluation and PI controller redesign using a relay-based experiment. The experiment data is used to evaluate the actual closed-loop. It is evaluated using classical robustness measures. A first-order plus dead-time(FOPDT) process model is estimated using the relay data. The controller redesign is performed using the robustness measures and a FOPDT model. The aim of controller redesign is to achieve a closed-loop with classical robustness measures around the redesign specifications. Simulation examples illustrate the redesign procedure.