Nonlinear L_2 anti-windup for enlarged stability regions and regional performance

In this paper, the nonlinear scheduled anti-windup approach of Zaccarian and Teel (2004) is revisited in light of a new sector condition which allows for more general results. The main contribution of the paper is to transform the hysteresis switching design into a Lipschitz (continuous) nonlinear control law which allows to guarantee global results with non exponentially unstable plants (this is a necessary condition for global results) and regional results with large stability regions with exponentially unstable plants. The main tool exploited here is a continuously parameterized Lyapunov function that leads to a nonlinear antiwindup compensator. The effectiveness of the approach is illustrated on simulation examples where it is compared to the switching approach.