Fixed-Dynamics Antiwindup Design: Application to Pitch-Limited Position Control of Multirotor Unmanned Aerial Vehicles

Abstract

In this paper we present and validate an anti-windup control design suitable to deal with saturated discrete-time linear plants. Following the modern approach to anti-windup design, the proposed synthesis procedure is based on the compensator paradigm in which the anti-windup controller acts on top of a baseline one, tuned to achieve desirable performance in the unsaturated regime. After extending existing ideas for continuoustime plants to their discrete-time counterparts, the design of the anti-windup compensator is carried out with a focus on computational efficiency and optimized performance in practical operating scenarios. The proposed approach allows one to design fixed-dynamics anti-windup compensators for possibly open-loop unstable plants using generalized sector conditions. Then, the synthesis procedure is applied to tune a fixed-dynamics compensator having the structure of a static compensator cascaded with a unit delay to avoid algebraic loops. Finally, the benefits of such anti-windup augmentation are assessed experimentally to counteract windup effects arising in the position control of multirotor UAVs when pitch limitations are imposed.