Antidisturbance Coordinated Path Following Control of Robotic Autonomous Surface Vehicles: Theory and Experiment

This paper presents a guidance and control law design method for coordinated path following of networked underactuated robotic autonomous surface vehicles (ASVs) under directed communication links. Each ASV is subject to model uncertainties and environment disturbances induced by wind, waves, and ocean currents. Antidisturbance coordinated path-following controllers are designed, featured with an inner-outer loop architecture. In the outer loop, a line-of-sight guidance scheme and graph theory are employed to design guidance laws for synchronized path following. In the inner loop, an extended state observer is developed to estimate the lumped disturbances, including the model uncertainties and environmental disturbances. Based on the estimated disturbances through the extended state observer, antidisturbance kinetic control laws are designed by resorting to a dynamic surface control method. The input-to-state stability of the closed-loop system is established by cascade theory and all error signals are uniformly ultimately bounded. Finally, the results of simulation and experiment are given to illustrate the effectiveness of the proposed antidisturbance coordinated path-following controllers for underactuated ASVs.