船舶航向跟踪系统自适应滤波反步终端滑模控制

针对船舶航向非线性系统,提出了一种基于自适应滤波反步法的终端滑模控制器. 系统由二阶非线性野本模型和舵机响应模型串联组成,考虑了模型不确定性和外部干扰等未知项,并由模糊系统对未知项进行在线逼近. 首先引入二阶低通滤波器,避免了对虚拟控制律的解析求导,从而简化了反步控制器的设计,而且滤波器的低通特性可大大减小测量噪声的影响;然后利用滤波反步法的结果设计了终端滑模面,并最终得到了使系统跟踪误差有限时间收敛的终端滑模控制器. 根据Lyapunov理论证明了闭环系统所有误差变量均是一致最终有界的. 仿真结果验证了所提方法的有效性. 

Terminal Sliding Mode Control for the Ship Course Tracking Problem Based on Adaptive Filtering Backstepping

A robust terminal sliding mode controller based on adaptive filtering backstepping was designed for the ship course tracking problem. The closed-loop system consists of the 2-nd order nonlinear Nomoto's autopilot model and the rudder response dynamics. The unknown terms, which were approximated online by using the fuzzy logic system, include the model uncertainties and the external disturbances. The filtering backstepping method avoids computing the derivatives of the virtual control by introducing a 2-nd order low pass filter, and consequently simplifies the backstepping implementation. Moreover, the low pass property of the filter decreases the effects of the measurement noise. Adaptive filtering backstepping was then used to design the terminal sliding surface, and finally a variable-structure controller was derived, which can guarantee the finite-time convergence of the tracking errors. According to the Lyapunov approach, all the error signals in the closed-loop system are proved to be uniformly ultimately bounded. Simulation results demonstrate the effectiveness of the proposed method.