Adaptive Finite-Time Trajectory Tracking Control for Coaxial HAUVs Facing Uncertainties and Unknown Environmental Disturbances

Abstract

In this paper, the problems of system design, dynamic modeling, and trajectory tracking control of coaxial hybrid aerial underwater vehicles (HAUVs) with time-varying model parameters and composite marine environment disturbances are investigated. It is clear that a stable transition between different media remains a challenge in the practical implementation of amphibious tasks. For HAUVs, accurate dynamic modeling to describe complex dynamic variations during vehicle takeoff from underwater to air is a huge challenge. Meanwhile, due to the rapid changes in model parameters and the external environment, vehicles are likely to fall into the sea during the cross-domain process. An integrated continuous dynamic model considering hydrodynamic changes is established by introducing a linear switching coefficient during the process of trans-medium motion. A nonsingular fast terminal sliding-mode control (NFTSMC) algorithm combined with adaptive technology is used to design the position and attitude of the controller. With no previous knowledge of external interferences and lumped uncertainties of the HAUV, the adaptive NFTSMC (ANFTSMC) algorithm achieves the control objectives; at the same time, the inherent chattering problems of sliding mode control (SMC) are weakened. The finite-time stability of the global system is proven strictly using a series of mathematical derivations based on Lyapunov theory. The effect of the controller applied is analyzed through a series of simulations with representative working conditions. The results show that the proposed ANFTSMC can realize a “seamless” air–water trans-medium process, which proves the superiority and robustness of the proposed control algorithm.

Reinforcement learning‐based finite‐time cross‐media tracking control for a cross‐media vehicle under unknown dynamics and disturbances

“…Therefore, although the FTC strategies have been used in many plants, these methods are not directly applicable to the CMV. An FTC policy utilising the non-singular terminal SMC was investigated for a coaxial CMV subjected to time-varying system parameters and external disturbances [27]. In reference [28], the authors developed a finite-time output feedback control method for a rotor CMV even when velocity measurements were not available.…”

“…In reference [28], the authors developed a finite-time output feedback control method for a rotor CMV even when velocity measurements were not available. However, both studies in references [27,28] neglected to account for specific wind and wave disturbances inherent in the cross-media motion of the CMV, and did not address the optimisation of the controller. In a word, the FTC techniques for CMV still need to be further developed.…”