Decoupled-architecture-based nonlinear anti-windup design for a class of nonlinear systems

This paper presents a comprehensive study on a dynamic nonlinear anti-windup compensator (AWC) design for nonlinear systems. It is shown that for asymptotically stable nonlinear systems, a full-order internal model control (IMC)-based AWC always exists regardless of the nonlinearity type. An alternative decoupled-architecture-based AWC offering better performance is proposed, wherein the selection of a nonlinear dynamical component plays a key role in establishing an equivalent decoupled architecture. Using the decoupled architecture, a quadratic Lyapunov function, the Lipschitz condition, the sector condition, and L ₂ gain reduction, a linear matrix inequality (LMI)-based AWC scheme is developed for systems with global Lipschitz nonlinearities. And by means of the local sector condition, a decoupled-architecture-based local AWC scheme (utilizing LMIs) for unstable and chaotic systems, which simultaneously guarantees a region of stability and the closed-loop performance for tracking-control applications, is derived. Simulation results establishing the effectiveness of the proposed AWC schemes are provided.