A PI Controller with Dynamic Set-Point Weighting for Nonlinear Processes

The paper deals with the control of nonlinear processes with 2DOF-PI controllers. A new and practical tuning method, based on recent ideas of immersion and invariance, is proposed for the dynamic adjustment of the set-point weight. The main attractive feature of the proposal is the possibility of assigning a reduced-order linear dynamics for the tracking response beyond the nonlinear characteristics of the process and the amplitude of the set-point changes. From a practical point of view the adjustment is performed by a simple sliding mode regime that accepts a straightforward implementation.