A Sigmoid-plane adaptive control algorithm for unmanned surface vessel considering marine environment interference

This article presents an application of a Sigmoid-plane (S-plane) adaptive control algorithm to an automatic steering system in the presence of uncertain parametric of the unmanned surface vessel (USV) and the unknown disturbance of the marine environment. Due to technical difficulties such as sensor noise, the marine environment disturbance is assumed to be unmeasured. To overcome this problem, an S-plane control is designed to resist marine environment disturbances by the improved adaptive term. Based on the gradient method, the USV heading model reference adaptive controller of the USV is designed, so that the USV has a certain ability to resist model parameter changes. Considering the uncertainty of marine environment interference, a model-reference-based S-plane adaptive controller for the USV is designed. After the reference of the USV course model, the S-plane adaptive control approach is employed to reduce the effect of the marine environment. It is proved that the USV course control system is stable, despite the adverse bad sea conditions. Finally, the course control simulation experiment for the USV with the unknown marine environmental interference is carried out. To demonstrate the benefits of the S-plane adaptive controller, the results are presented in comparison with a Lyapunov method controller. The results show that the S-plane adaptive controller is robust to the changed model parameter and external disturbances.