Research On Modeling And Tracking Control Of An Underwater Manipulator For UUV Docking

In the era of increasing consumption of mineral resources on land,the ocean with rich resources has become another battlefield of competition among countries,and to a large extent marine development technology determines the development potential of a country.With low construction cost and good performance,unmanned underwater vehicles(UUV)plays a great role in various underwater tasks in civilian and military fields,but limited by endurance,its working range is relatively smaller than that of large manned submersives.Underwater docking technology can directly complete the energy supplement and data exchange tasks of UUV under the sea surface,effectively prolong the working time of UUV,improve the efficiency and concealability of UUV during operation.The current recovery method mainly relies on UUV to actively meet with the docking device in the static state,which has high control requirements for UUV,and the volume of docking system is large,and there is a risk of collision between UUV and the underwater platforms.This paper proposed a docking system using underwater manipulator to actively capture UUV,and studied the docking process between the underwater manipulator and UUV,and the prototype of the underwater manipulator system is developed and tested.Firstly,based on the structure of the manipulator,the D-H method was used to bulid the kinematic modeling,and the relationship between the position of capture point and the motion of each joint was obtained by solving the kinematic model of the manipulator.Based on Monte Carlo method,the workspace of UUV capture of underwater manipulator is calculated.Lagrange method was supplied to drive the underwater manipulator from the perspective of dynamics,and its mathematical model was established.The inertial matrix,Coriolis force and centrifugal force,and gravity terms of the dynamics equation of the manipulator were deduced.Based on Morison formula,the fluid force on the underwater manipulator was calculated,and finally its complete dynamic model was obtained.According to the operation mode of underwater manipulator,the trajectory of docking UUV is planned.With the cubic polynomial interpolation algorithm used,the trajectory of the underwater manipulator was planned and simulated,and the curves of each joint of the underwater manipulator with time were obtained.Aiming at the characteristics of multi-coupling and nonlinear in the operation process of underwater manipulator,a fuzzy self-adaptive sliding mode controller was designed to control the movement trajectory of it.The simulation model of underwater manipulator and its control system was built in Matlab/Simulink platform.The motion process of tracking and capturing UUV by underwater manipulator was simulated and analyzed,and the joint variable curves of each joint were obtained.The simulation results show that each joint can track the dynamic trajectory of UUV under the action of the controller,and the tracking error is less than 0.05 m,which verifies the effectiveness of the controller.The underwater manipulator prototype and the test platform was bulit,and the lake test of docking UUV by underwater manipulator prototype was completed.In the test,the joint of the manipulator prototype worked normally,and the UUV was successfully docked,and the feasibility of the scheme of recovering unmanned underwater vehicle with underwater manipulator is verified.