Yiyi Xiang

In general, a rotating reference frame moving along the reference path is established in the unmanned surface vehicle (USV) path following method based on line-of-sight (LOS) guidance, and good following performance is achieved for the paths with small curvature. However, this method often results in significant deviations at multiple sharp turns due to underactuation. Accordingly, a new path following method via the rotating reference frame is proposed in this article. First, it is proven that there must exists an optimal rotating frame angle, by which USV can follow the reference path precisely. Second, a novel rotating reference frame adaptive law is designed to track this optimal angle, by which the frame angle rotation rate can be regulated for adapting to variation of path curvature and environmental disturbances. Stability analysis proves that the proposed method can follow multisharp-turn reference path in presence of disturbances. In addition, the desired constrained conditions determining the bounds of desired speed and reference path curvature under thruster saturation are developed. Path following can be achieved only if the desired speed and path curvature remain within these bounds. Finally, both simulation and experiment results validate effectiveness of the proposed method by comparing with the existing LOS guidance methods.