Integral control of stable MIMO nonlinear systems with input constraints

This paper presents a novel anti-windup integral controller for a stable multi-input multi-output nonlinear plant. We use tools from projected dynamical systems theory to force the controller state (and thus its output) to remain in a “permitted” (compact and convex) region, regardless of the plant behaviour. Then, using results from singular perturbation theory, we find a sufficient condition on the controller gain ensuring, under suitable monotonicity assumptions on the plant, closed-loop stability and reference tracking for a feasible set of constant references.