Formation Control and Stability Analysis of Underactuated Unmanned Surface Vehicles Based on Improved Extended State Observer: Addressing Disturbance Challenges

This paper focuses on unmanned surface vehicles (USVs) and introduces a formation control method that addresses both preset transient performance and steady-state performance constraints for fixed-configuration formations of USVs, taking into account model uncertainties and external disturbances. By designing the control law for different regions, we overcome the singularity issues inherent in traditional PID control. The control algorithm is integrated with graph theory to achieve effective formation control of the USVs. A dimension-reduced extended state observer is employed to detect unknown time-varying side-slip angles and external disturbances, providing accurate estimation and compensation for these composite disturbances, including ocean current interference. The stability of the ship formation control law is verified using Lyapunov theory. Additionally, the cascade system stability analysis method is used to demonstrate that the closed-loop system possesses input-to-state stability. Simulation results indicate that this method significantly enhances the stability and robustness of the USV formation.