Some new results on anti-windup-conditioning using the Weston-Postlethwaite approach

Anti-windup (AW) compensation, commonly used to counteract performance and stability problems due to saturation non-linearities in the actuator of primarily linear control systems, is revisited in terms of the approach of Weston & Postlethwaite (W&P). Their parameterization consists of a filter M and a linear model of the plant dynamics. Several consecutive results have been obtained: First, the W&P-approach is extended to a more generic, recently established L₂-problem formulation for AW-compensator design; second, it is shown that the most suitable choice for M is based on a plant coprime factorization; third, it is proved that the coprime factorization technique can achieve optimal performance once the designer intends to recover nominal linear controller performance for a a reasonably generic class of linear control problems. This significantly facilitates the L₂-design of full-order AW compensators. As a final result, linear matrix inequality (LMI)-design conditions for this AW-configuration are provided.