Enhanced trajectory tracking for AUVs: Adaptive Super-Twisting Sliding Mode Control with disturbance observer

This paper proposes a novel composite disturbance rejection controller that enhances the trajectory tracking performance of Autonomous Underwater Vehicles (AUVs), which is essential for achieving autonomy and precise navigation despite uncertainties in model parameters and time-varying disturbances. The controller adeptly merges Adaptive Super-Twisting Sliding Mode Control (ASTSMC) with a Super-Twisting Nonlinear Disturbance Observer (STNDO), which has effectively enhanced its ability to counteract disturbances. It is worth noting that the controller operates without precise model information and prior knowledge of disturbance boundaries, and this feature offers high adaptability. Due to its adaptive law and a reduced parameter set, the controller offers parameters that are not only straightforward to tune but also exceptionally suitable for practical deployment. The stability of the closed-loop system with the composite disturbance rejection controller is validated via the Lyapunov concept. Numerical simulations conclusively demonstrate the controller’s superiority in countering time-varying external disturbances, even under hydrodynamic parameter errors of up to 40%. Moreover, real-time experiments across different operating conditions have validated the effectiveness and robustness of the proposed controller, which showcases its potential as a robust solution for advanced AUV operations.