An Enhanced Trajectory Tracking Control of the Cooperative Ship Formation Based on Leader-Follower Strategy and Fixed Time Disturbance Observer

This paper proposes a cooperative formation trajectory tracking control method to address the challenges of actuator saturation nonlinearity and environmental disturbances in underactuated ship formation (USF) control in marine environments. First, The system is based on a leader-follower strategy, and designs a trajectory tracking guidance law for each follower ship, which includes the desired yaw angle and surge velocity. Second, to address the nonlinearity problem caused by ship input sat-uration, an auxiliary state system is also designed, Through the use of fixed-time formatiom controller(FTFC), the error between the expected surge velocity and yaw angle in the guidance law and the actual values can converge within a fixed time. In addition, to address uncertain disturbances in marine environments, a fixed-time disturbance observer(FDO) is incorporated into FTFC to accurately estimate environmental disturbances. Finally, the control method achieves the desired formation configuration. Using Lyapunov stability theory, the paper proves that the fixed-time disturbance observer and fixed-time formation controller(FDO-FTFC) algorithm satisfies semi-global uniform ultimate boundedness convergence. Simulation and comparison results show the effectiveness of the proposed control strategy.