Robust nonlinear reference filtering for constrained linear systems with uncertain impulse/step responses

A method based on conceptual tools of predictive control is described for solving tracking problems wherein pointwise-in-time input and/or state inequality constraints and model uncertainties are present. It consists of adding to a primal compensated system a nonlinear device called predictive reference filter (PRF) which manipulates the desired trajectory in order to fulfill the prescribed constraints. Provided that an admissibility condition on the initial state is satisfied, the control scheme is proved to fulfill the constraints and be asymptotically stable for all the systems whose impulse-response and step-response descriptions lie within given uncertainty range