Multiple anti-windup loops under multiple static activations: Enlargement of the domain of attraction

Anti-windup design is an intuitive and efficient way to deal with input saturation nonlinearities. In the classic anti-windup design, the compensator is set to be activated immediately as the control signal saturates the actuator. An important innovation in the anti-windup activation mechanism is to delay the activation of the anti-windup mechanism until the saturation reaches to a certain severity which led to a performance improvement of the resulting closed-loop system. More recently, it was shown that by activating a static anti-windup mechanism in anticipation of actuator saturation, significant further performance improvements can be achieved in comparison with the delayed activation design. In addition, we have combined both the delayed and anticipatory activation mechanisms, to develop the multiple activation strategy, in terms of ℒ₂ gain performance. This paper furthermore considers the problem of enlarging domain of attraction and demonstrates that the multiple activation of a static multiple feedback anti-windup mechanism would also lead to significant performance improvements over both the immediate and delayed activation schemes.