Research On Underwater Dual-arm Manipulator Collaborative Operation System

Recently,with the increasing frequency of marine activities,underwater vehicles technology has been widely used in ocean activities.And the research of underwater manipulator has been carried out in various countries,as the main operating equipment of underwater vehicles.With the complexity and diversity of underwater tasks,two or more manipulators were required to collaborate to complete the work successfully or increase efficiency in many underwater scenarios.In the application of practical multi-manipulator system,the cooperative operation system of underwater dual-arms has been the most common and widely used.Due to limited load capacity of underwater vehicles,while aiming at the complex underwater environment,it is of great practical significance to design underwater dual-arm operating system with high integration,diverse functions,flexible operation and accurate control.In this paper,the underwater dual-arm cooperative operation system has been designed,including the key technical such as the configuration design of underwater dual-arms,the development of integrated joint motor and the design of motion control software,control system and the design of collaborative operation mode,while verified the validity of the system through underwater test.Firstly,by querying the current research situation at home and abroad,combined with the requirements of the practical research project and the development trend of underwater manipulator,the underwater dual-arms with the left and right symmetrical 4 degrees of freedom 5 functional electrically driven manipulator configuration have been designed as human arm.The kinematics model of the dual-arms have been established by the design scheme,and the simulation analysis of kinematics is carried out in Matlab,while the working space of the dual-arms has been obtained and analyzed.The analysis verified that the configuration of designed dual-arms can realize the cooperative operation task and meet the project function requirements.Secondly,the control system design and realization of the cooperative operation system of underwater dual-arms have been carried out.It adopted the onshore/underwater level two control structure,while the onshore part is the onshore monitoring terminal with the human-computer interaction interface and the underwater part is the joint motor controller of the manipulator.The data interaction has been realized between the onshore monitoring terminal and each joint motor controller of the underwater manipulator by establishing one-to-many CAN bus communication network.The operator can control the manipulators through the onshore monitoring terminal,and monitor the working state of the manipulator and the running state of each joint motor.Then,the integrated joint motors of underwater manipulators have been developed with integration and high power density.The structure of watertight joint motor has been designed by means of "O-ring and hydraulic compensation",and the motion control software of joint motor has been developed based on the design of ?C/OS-II embedded real-time operating system.The trajectory planning of joint motor movement in joint space has been carried out by using three polynomial interpolation method,and the precise closed-loop position control of joint motor output shaft has been carried out by PID motion controller.Next,three kinds of cooperative operation methods which are the "Parallel Grabbing",the " Front and Rear Grabbing " and the " Hugging " have been designed for the underwater dual-arms cooperative operation system,while the "One-click " automatic operation function has been designed to maintain the synchronization and symmetry in the movement of the left and right manipulators in order to reduces the operational difficulty of the dual-arms cooperative operating system.Finally,the test of the cooperative operation system of underwater arms manipulator has been carried out,from the single test of joint motor to single manipulator test,and finally to the joint adjustment test of the arms operation system,from the onshore test to the underwater test,and the test verified the control performance and operation ability of the underwater dual-arms cooperative operation system.