Distributed leaderless formation control for multiple autonomous underwater vehicles based on adaptive nonsingular terminal sliding mode

In this study, we address the formation control problem of multiple autonomous underwater vehicles (AUVs) in the presence of model uncertainties and ocean-current disturbances. Specifically, we propose a robust distributed leaderless formation control strategy by cross-coupling a synchronous control technique, a nonsingular terminal sliding-mode control approach, and an adaptive control method. We enhance the robustness against system uncertainties by redefining the cross-coupling errors and ensure that the finite-time tracking error converges to zero from any initial value via the designed adaptive nonsingular terminal sliding mode control, which also eliminates the chattering problem. A major advantage of our adaptive control law is neglecting the requirement of any prior knowledge about the upper bounds of the model uncertainties and ocean-current disturbances. Our comparative simulation results demonstrate the effectiveness of the proposed distributed leaderless formation control scheme.