Fault-tolerant Control for Trajectory Tracking of Underactuated Unmanned Surface Vehicles with Actuator Faults

As an effective equipment for ocean resources exploration, USVs have a wide range of applications in civil and military fields, which undertake long-term, large-scale, low-cost marine scientific research and engineering tasks. In practical applications, USVs are usually underactuated, which means these USVs equipped with fewer actuators than degrees of freedom. When carrying out tasks such as target tracking or stalking, USVs are usually needed to track the target as soon as possible, which results in a high requirement to the tracking speed and accurace of USVs. In this paper, by taking into account the actuator fault tolerant control (FTC), a tracking control scheme is proposed for an underactuated unmanned surface vehicle (USV). Firstly, a uniform actuator fault model is constructed, which can be used to fully describe three actuator faults including stuck, outage, and loss-of-effectiveness. Secondly, a controller, which is based on the backstepping method and a tan-type barrier Lyapunov function (BLF), is designed to constrain the errors of position and heading angle between an underactuated unmanned surface vehicle and a virtual leader. Moreover, to solve the "explosion of complexity" problem caused by the virtual control variable differentiation, a biological inspiration model is established. Finally, simulation results demonstrate the effectiveness of the designed control scheme.