An Event-based PI controller autotuning technique for integral processes

In this paper we propose an autotuning methodology for a symmetrical send-on-delta PI controller for integral processes. In particular, a technique already proposed for self-regulating processes is extended to deal with non self-regulating processes. It is based on the estimation of the parameters of an integrator-plus-dead-time transfer function by means of a single relay-feedback experiment where a roughly tuned PI controller is also used in the feedback system. Then, new controller parameters can be selected based on the identified process model. Simulation results demonstrate the effectiveness of the methodology.