针对目前欠驱动船舶航迹跟踪控制难以实现跟踪任意可行航迹问题,提出一种运动规划方法。利用多项式拟合,并结合船舶动力学模型,通过离散期望点规划出操作性可实现的全部期望姿态。同时,为实现欠驱动船舶的航迹快速跟踪控制,提出一种全局指数航迹跟踪控制律。引入微分同胚变换,建立两个级联的子系统构成的航迹跟踪误差动态方程;基于反步法的设计原理,运用Lyapunov直接方法对变换后的误差系统设计了全局指数航迹跟踪控制律。仿真结果验证了所提出的全局指数航迹跟踪控制律能够有效实现跟踪任意可行航迹。
In order to realize tracking arbitrary specified trajectory, a motion planning method is presented. All the desired attitudes are obtained by combining cubic spline interpolation, ship dynamic model, and discrete expected dots. Meanwhile, in order to realize fast tracking trajectory of underactuated surface vessels, global exponential tracking control law is proposed. Trajectory tracking error dynamic equation consists of two cascade subsystems based on diffeomorphism transformation. Then global exponential tracking control law is designed by using backstepping for error subsystems. The results of simulation experiments indicate that the proposed controller can effectively track arbitrary specified curve trajectory.