Autonomous Underwater Vehicle Research On Recovery Dockingand Trajectory Tracking Control

With the rapid development of Marine economy in the world,countries all over the world pay more and more attention to Marine resources.There has been continuous innovation in the relevant theories and technical innovation of underwater robots.As an important tool for today’s marine search,autonomous underwater robots have been widely used in the fields of energy,military,marine environment monitoring and underwater search and rescue,The functional innovation and application of autonomous underwater vehicle(AUV)are paid more and more attention by researchers all over the world.This thesis takes the independently developed "T-SEA II" AUV as the research object,focuses on the method of AUV three-dimensional trajectory tracking control,and participates in the development of AUV autonomous recovery and docking system.The main work is as follows:Firstly,the development status of AUV at home and abroad is analyzed,and the research status and development trend of AUV docking device and 3D trajectory control method at home and abroad are analyzed.According to the actual situation and demand of "T-SEA II" AUV,mathematical modeling is carried out for "T-SEA II" AUV,including kinematics and dynamics models.The overall scheme of AUV recovery docking and trajectory tracking control system of "T-SEA II" AUV is developed.This thesis focuses on the three-dimensional trajectory tracking problem of AUV.In order to solve the three-dimensional trajectory tracking control problem of AUV under current interference,controller overshoot and model uncertainty,a virtual guide with adaptive law is designed in the kinematics controller,which reduces the current interference and improves the stability of the system.In the dynamic controller,a second-order differential tracker is introduced to ensure that the transition time of longitudinal speed control is short and there is no overshoot;Radial basis function neural network(RBF)is used to approximate and compensate the uncertainty of AUV model.The simulation results show that the controller can effectively overcome the influence of ocean current and model uncertainty,suppress buffeting and overcome overshoot.Then,considering the harsh marine natural environment,there are many problems in the trajectory tracking control of conventional AUV,such as slow convergence speed,easy saturation of controller output,uncertainty of its own model and so on.A dual closed-loop trajectory control strategy based on adaptive finite time and reduced order extended observer is proposed.According to the time scale of control,it is divided into position controller and attitude controller.The position controller is designed by adaptive finite time method,which can accelerate the convergence speed of AUV position variables;The attitude controller is designed by using the idea of dynamic surface control,integral sliding mode,state observer and new reaching law to achieve rapid convergence and stability of the desired attitude.The three-dimensional simulation environment shows that the controller designed in this chapter is higher than the common trajectory tracker in convergence speed,control accuracy,robustness and tracking effect,and can better meet the trajectory tracking control needs of AUV.Subsequently,author participated in the design and development of the autonomous docking test control system of the "T-SEA II" AUV host computer and docking dock,and carried out the AUV trajectory tracking control system test and autonomous recovery docking lake test in Suzhou Shazhou lake.The experimental contents mainly involve the underwater polygon tracking control system and continuous recovery docking test.Continuous groups of actual measurements in different trajectories are used to verify the designed controller and trajectory tracking control technology,The experimental results show that the trajectory tracking control of AUV is accurate and the success rate of recovery and docking is high.