Predefined-time disturbance estimation and tracking control for AUVs with actuator saturation on SE(3)

This article investigates the tracking control with the unconstrained attitude manoeuvrability for autonomous underwater vehicles (AUVs) under input saturation and model uncertainties. With this goal in mind, a geometric predefined-time control approach is suggested on the special Euclidean group SE(3), incorporating backstepping, disturbance observer, and anti-saturation auxiliary system. Firstly, considering that designing control schemes in the parameterized space cannot meet the demands of vehicles during aggressive-attitude maneuvers effectively, which is essentially due to the lack of global or unique attitude descriptions in Euler-angles and quaternion, the tracking control scheme is built on the SE(3). Subsequently, a more promising mapping from SE(3) to Euclidean space is introduced to construct a novel configuration error vector that is positively correlated with the configuration error of AUVs, boosting the control performance during large-angle maneuvers significantly. Then, a predefined-time disturbance observer and saturation compensator are presented to exclude the adverse impacts of model uncertainties and input saturation on the AUV system. Finally, an anti-saturation controller is proposed, which ensures that the error signals almost globally converge to a small neighborhood around the origin within a predefined-time. Various numerical experiments are showcased, proving the advantages of the suggested control strategy in multiple dimensions.