Prescribed time observer based trajectory tracking control of autonomous underwater vehicle with tracking error constraints

This paper addresses the trajectory tracking control problem of the autonomous underwater vehicle with tracking error constraints and prescribed time convergence. In view of the fact that underwater vehicle is inevitably influenced by unknown external disturbances and input saturation, a disturbance observer is first proposed to achieve prescribed time disturbance attenuation. By virtue of the proposed observer, the observation error will arrive and maintain at a user-defined compact set in a prescribed time, which lays the foundation for subsequent control design. Then, an auxiliary dynamic system with time varying gain is constructed to deal with the input saturation phenomenon. Finally, a robust tracking control scheme is derived by integrating the proposed observer and auxiliary dynamic system into the prescribed performance control architecture, which results in both prescribed time convergence and transient performance constraints in the presence of input saturation and disturbances. Numerical simulation studies are carried out to illustrate the superiority and benefits of the proposed algorithm.