A disturbance rejection anti-windup framework and its application to a substructured system

In this paper, we consider the disturbance rejection problem of stable systems with input saturation based on the anti-windup (AW) framework developed by Weston and Postlethwaite (W&P) [17]. The performance is improved by explicitly incorporating a transfer function representing the effect of the disturbance on the nonlinear loop during the AW compensator synthesis. The suggested AW-design approach improves disturbance rejection performance over the design framework usually suggested for the coprime-factorization based W&P-approach. For this, an extra degree of freedom is exploited for the coprime factorization which usually results in an implicitly computed multivariable algebraic loop for the AW-implementation. Suitable suggestions are made to overcome the algrabraic loop through explicit computations. The approach is applied to the control of a dynamic substructured system (DSS) subject to a measurable excitation/ disturbance signal and actuator limits. The benefit of this approach is demonstrated for a quasi-motorcycle DSS simulation.