A noncausal approach for the improvement of PID control performances

A new approach for the improvement of the set point following performances achieved by a PID controller is presented in this paper. Basically, the devised methodology consists of designing, by means of a stable dynamic inversion procedure, a suitable command signal to be applied to the closed-loop control system in order to achieve a desired transient response when the process output is required to assume a new value. A closed-form solution of the problem is obtained, making the technique suitable to be applied in the industrial context. Simulation and experimental results show that high performances are obtained despite the presence of model uncertainties and, above all, independently on the PID tuning. Thus, the PID gains can be selected in order to guarantee good load rejection performances without impairing the set-point transient responses.