Finite-time unknown observer based coordinated path-following control of unmanned underwater vehicles

In this paper, a coordinated path-following control (CPFC) scheme is proposed for multiple unmanned underwater vehicles (UUVs) under undirected communication links. Each UUV is subject to complex unknowns involving model parameter perturbations and time-varying external disturbances. In light of individual path-following control, the coordinated guidance laws are developed to guide UUV surge velocities and yaw velocities, simultaneously. By virtue of graph theory, the neighbor information based path update laws are further employed to achieve synchronized tracking. Within the kinetics controller design, a finite-time unknown observer (FTUO) is utilized to assist in cancelling the lumped unknowns within a short time. Additionally, the FTUO-based distributed robust controllers are developed for UUVs and guarantee the guidance velocity signals generated by coordinated guidance can be successfully tracked. Strict stability analysis is proved in the sense of Lyapunov. Finally, simulation results and comparisons substantiate the efficacy and superiority of the developed CPFC scheme.