This work considers a finite-time command filtered course tracking problem of ships with unknown bounded disturbances, unmodelled dynamics and input saturation. By melting command filter technique into backstepping design, a finite-time control scheme is proposed, which overcomes the ‘explosion of complexity’ and ‘singularity’ problems resulted from the calculation of repeated derivatives of virtual control inputs in the conventional backstepping method. A hyperbolic tangent function is adopted to estimate saturation with a bounded estimation error in order to guarantee that the saturation function acting on the rudder angle can be differentiable, where the rudder angle is considered as a new state variable whose initial value is zero. The finite-time disturbance estimator is constructed to provide the estimation of compounded uncertain item derived from unmodelled dynamics and external disturbances. Simulation results and comprehensive comparisons are used to demonstrate the effectiveness and superiority of the proposed control scheme.

这项工作考虑了具有未知有界扰动、未建模动力学和输入饱和的船舶的有限时间命令过滤航向跟踪问题。将指令滤波技术融入反演设计中，提出了一种有限时间控制方案，克服了传统反演方法中计算虚拟控制输入的重复导数导致的“复杂性爆炸”和“奇异性”问题。采用双曲正切函数估计饱和度，估计误差有界，以保证作用在舵角上的饱和度函数是可微的，其中舵角被认为是一个初始值为零的新状态变量。构造有限时间干扰估计器以提供对来自未建模动力学和外部干扰的复合不确定项的估计。仿真结果和综合对比证明了所提出的控制方案的有效性和优越性。