A noncausal approach for PID control

A new approach for the improvement of the set-point following performances achieved by a PID controller is presented. Basically, it consists of applying a suitable command signal 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. This command signal is determined by means of a stable input–output procedure for which a closed-form solution is presented, thus making the technique suitable to implement in the industrial context. Simulation and experimental results show that high performances are obtained despite the presence of model uncertainties and, above all, almost 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.