Research On Adaptive Dynamic Surface Control For Full Actuated Ship Trajectory Tracking

For ships that require high maneuverability and high safety,such as floating oil production-storage-offloading ships,shuttle transportation cruises,supply ships and semi-submersible drilling platforms,we generally use full actuated configuration to achieve their objective.When they carry out specific tasks such as deep-sea exploration,submarine pipeline construction,supply and offshore oil drilling,it's necessary to follow the desired trajectory accurately.Because of the environment and characteristics of ships,the ships with multiple coupling and strong nonlinearity are inevitably subjected to environmental disturbances and dynamic uncertainties.Design on the ship trajectory tracking control has great challenges.Therefore,it is of great theoretical significance and practical engineering value to study the trajectory tracking control of the full actuated ship.Firstly,for the trajectory tracking problem of 3-DOF full actuated ship with unknown external environment disturbances,an adaptive dynamic surface sliding mode control method with disturbance observer is proposed.The observer is designed to provide estimations of disturbances and feedforward compensation for control amount.The adaptive laws are used to estimate bounds of disturbance observer errors and improve the control precision.Dynamic surface control technique is combined to construct controller so that the differential expansion problem can be avoided.Secondly,for the trajectory tracking problem of 3-DOF full actuated ship with model uncertainty and unknown external environmental disturbances,an adaptive recursive sliding-mode dynamic surface control method with nonlinear gains is proposed.Neural networks are introduced to provide estimations of model uncertainties.The adaptive laws are used to estimate bounds of neural network errors and unknown external environmental disturbances.Recursive sliding-mode surface which considers the relationship between position and velocity error is designed.A kind of nonlinear gain function is applied to construct the dynamic surface control law.The non-fragile to the perturbation of its own parameters is enhanced.Thirdly,for the trajectory tracking problem of 3-DOF full actuated ship with unknown ship model parameters,external environmental disturbances and immeasurable velocity vectors,a neural network observer based adaptive recursive sliding-mode dynamic surface output feedback control method with low frequency learning is proposed.The adaptive neural network observer is designed to estimate ship velocity vectors,and a neural network is introduced to provide estimations of the unknown model section.Recursive sliding-mode dynamic surface control technique is used to construct the control law.The low frequency learning method is applied to eliminate the high frequency oscillation control signal caused by external disturbances.Finally,simulations of line trajectory and circular trajectory tracking based on a supply ship are carried out,and the results show that control outputs are reasonable and effective,the proposed controller has strong robustness for external environmental disturbances and unknown model section.With fast tracking responding speed and high accuracy,the control objectives can be achieved.