NNFFC-adaptive output feedback trajectory tracking control for a surface ship at high speed

• Published in: Ocean engineering 2011-09, Vol.38 (13), p.1430-1438
• Main Authors: Zhang, Li-Jun, Jia, He-Ming, Qi, Xue
• Format: Article
• Language: English
• Subjects: A surface ship at high speed; Adaptive output feedback; Applied sciences; Computer simulation; Control surfaces; Dynamical systems; Exact sciences and technology; Ground, air and sea transportation, marine construction; High speed; Hydrodynamic damping; Marine; Marine construction; Neural network feedback–feedforward compensator; Nonlinear dynamics; Ships; Tracking; Trajectory tracking control
• ISSN: 0029-8018; 1873-5258
• DOI: 10.1016/j.oceaneng.2011.07.006

An adaptive output feedback controller based on neural network feedback–feedforward compensator (NNFFC) which drives a surface ship at high speed to track a desired trajectory is designed. The tracking problem of the surface ship at low speed has been widely investigated. However, the coupling interactions among the forces from each degree of freedom (DOF) have not been considered in general. Furthermore, the influence of the hydrodynamic damping is also simplified into a linear form or neglected. On the contrary, coupling interactions and the nonlinear characteristics of the hydrodynamic damping can never be neglected in high speed maneuvering situation. For these reasons, the influence of the nonlinear hydrodynamic damping on the tracking precision is considered in this paper. Since the hydrodynamic coefficients of the surface ship at high speed are very difficult to be accurately estimated as a prior, it will be compensated by NNFFC as an unknown part of the tracking dynamics system. The stability analysis will be given by the Lyapunov theory. It indicates that the proposed control scheme can guarantee that all the signals in the closed-loop system are uniformly ultimately bounded (UUB), and numerical simulations can illustrate the excellent tracking performance of the surface ship at high speed under the proposed control scheme. ► A nonlinear controller is designed to drive a ship at high speed to track a desired trajectory. ► Output feedback dynamic compensator is designed to stabilize the linear part of the system. ► Observer is adopted to estimate the unmeasured states about velocities and accelerations. ► NNFFC can compensate for the influence of the time-varying hydrodynamic damping.