ROV Underwater Manipulator Operation Simulation System Research

A cable-operated underwater robot Remote Operated Vehicle(ROV)is one of the most commonly used operational equipment for deepwater underwater engineering.ROV underwater manipulators are of great help in the operation and maintenance of underwater facilities as well as in exploration and research tasks in harsh underwater environments.Underwater robotic hands have been used for a number of complex subsea operations such as inspection of the seabed,operation of oil field installations in underwater environments,and personnel search and rescue missions.In view of the complex work tasks,difficult personnel operation,low economic efficiency,and high safety costs that ROVs encounter during actual operations,this paper designs an underwater robotic motion control operation simulation system based on the Robot Operating System(ROS)and develops an operation scenario for the actual underwater robotic operation of starting and stopping underwater valves In this paper,we design a simulation system based on the Robot Operating System(ROS)for underwater manipulator motion control operation,and develop an operation plan for the actual underwater manipulator valve opening and stopping operation.The feasibility of the operation plan and the practicality of the simulation system are verified through simulation,which provides a reliable basis for the actual underwater operation.First,the kinematic and kinetic equations are used to establish the mathematical model of Orion7P underwater manipulator.The kinematic model of the underwater manipulator is established based on the Euler angle and D-H methods,and the reachable workspace of the manipulator is analyzed and its Jacobi matrix is derived to make the nonlinear partial differential relationship between the position of the end-effector and the position value of each joint of the manipulator partially linearized.The dynamics of the underwater manipulator is modeled and analyzed based on the Lagrangian equation based on the principle of energy conservation law,which is characterized by strong nonlinearity and multiple perturbations in the working scenario of the underwater manipulator.Secondly,the motion characteristics of the six-degree-of-freedom underwater manipulator are analyzed,and the trajectory planning of the manipulator is carried out in joint space using cubic,quintuple and higher-order polynomials,and the trajectory planning of the manipulator is carried out in Cartesian space using linear and circular arcs,based on which,the autonomous underwater manipulator motion planning based on Dynamical Systems(DS)imitation learning is proposed to build The DS mathematical model of the underwater manipulator,the sufficient conditions for the global stability of the DS system are derived,and the autonomous obstacle avoidance function is added on the basis of the existing one,so that the underwater manipulator can perform autonomous obstacle avoidance operation under complex conditions,and the feasibility of the autonomous operation of the underwater manipulator is verified by simulation.Then,the ROV underwater manipulator operation simulation system is established.Based on the 3D model of the underwater manipulator,it is accurately modeled and integrated into the simulation system.Based on the mathematical model of the underwater manipulator,the kinematics and dynamics of the simulation system are designed in real time,and based on the parameters obtained from the simulation,the impedance control module of the underwater manipulator based on DS imitation learning is designed to realize the real-time control of the manipulator in the underwater simulation environment.The above modules are then packaged into ROS nodes,and a reasonable communication method is designed to connect the modules to complete the overall simulation system.Finally,the underwater manipulator is operated in the underwater simulation environment for non-contact motion simulation,and the simulation results can verify the correctness of underwater manipulator modeling and reasonable motion planning.On this basis,the ROV underwater operation scenario simulation environment is built based on the Lingshui 17-2 project as a prototype,and the ROV underwater manipulator is simulated to operate the valve start/stop of the subsea oil and gas production equipment according to the actual working conditions.The results verified the feasibility of the autonomous operation of the ROV,and it can accurately reflect the mechanical interaction and geometric collision between the simulation objects,and can monitor the parameters of the simulation system dynamically in real time,which can help the feasibility and safety preview of the typical operation of the ROV,different operating conditions and equipment renewal.