Research On Track Control Of Underactuated Autonomous Underwater Vehicle

Autonomous Underwater Vehicle(AUV)plays an important role in marine scientific investigation,underwater exploration and marine target exploration due to its higher mobility and system reliability.However,the realization of stable trajectory tracking of the AUV control system is the key to ensure its stable and reliable underwater work.In this paper,a tracking controller is designed to solve the problems of ocean current,input limitation,model uncertainty in the underactuated AUV system.Firstly,the mathematical model of AUV motion control under actuation is established.Based on the actual situation,the transformation relationship between the inertial coordinate system and the volume coordinate system is reasonably simplified.Then,the five degrees of freedom kinematics model of the underactuated AUV is established.According to the Newton-Euler equation of the rigid body,the dynamics model is obtained through force analysis.Meanwhile,the characteristics of underactuated AUV control are analyzed to design a strong robust nonlinear controller.Secondly,aiming at the limitation of actuator amplitude and ocean current disturbance in the horizontal plane track tracking control of the underactuated AUV,the virtual velocity control strategy is proposed.The virtual velocity is processed by a filter to reduce the complexity of the control algorithm.Based on nonlinear disturbance observer and adaptive neural network sliding mode controller,a horizontal track tracking controller is designed to effectively reduce the influence of ocean current disturbance and actuator amplitude limitation on the controller.The simulation results show that the designed controller not only responds faster,but also has higher accuracy and robustness.Finally,considering the uncertainty of model parameters in the space 3D track tracking control system of underactuated AUV,an adaptive nonsingular terminal sliding mode controller based on a perturbed extended observer is designed.The virtual velocity control strategy is used to stabilize the position error of AUV 3D track.In order to reduce the complexity of derivation calculation,dynamic surface control is used to filter the virtual velocity.And,the model uncertainty and the influence of ocean current are suppressed by the disturbance extended observer.Through simulation and comparison,the effectiveness of the controller is fully demonstrated and the output of the controller is smoother.