Managing Unwinding in Quaternion-Based Antiwindup Compensation for Constrained Rigid Body Attitude Control

This article investigates the problem of unwinding in quaternion-based antiwindup compensation for constrained rigid body attitude control. Quaternion-based compensators and controllers can lead to the unwinding phenomenon if the double covering problem of the rigid-body-attitude space is not considered. Moreover, actuator saturation is a source of performance degradation or even instability of control systems. Therefore, in this article, a quaternion-based antiwindup compensator is proposed and stability proofs are derived that provide asymptotic stability properties and a propensity to avoid attitude unwinding. Simulation results illustrate that the proposed method leads to significantly smaller rotation of the rigid body than an earlier antiwindup approach that does not address the unwinding phenomenon.