Nonholonomic Constraint Underwater Welding Robot Motion Control And Process Parameter Cooperation Research

With the frequently development of marine activities, many kinds of underwater structures appeared. Because of the long serving under water, some steel components are damaged, need to be repaired in time. In response to this demand a kind of moving platform equipped with manipulator form underwater welding robot model was designed. The underwater moving platform could adsorbed on the surface of the steel structure by permanent magnet wheels, and local drainage cover is installed at the end of the manipulator with welding torch in it. Local dry welding methods was applied in all-position welding operations. This paper mainly study on robot kinematics and the key parts drain cover for local dry underwater welding and welding technology. The main research contents are:(1) Kinematics model of nonholonomic constraint mobile welding robot is established, including the kinematics model of wheeled mobile platform and welding manipulator. The forward and inverse kinematics solutions are calculated. The planning trajectory and movement time of the mobile platform and the welding manipulator are given, then calculate the motion parameters by inverse solution, and input the results of the calculation to ADAMS to simulate the all-position welding trajectory.(2) According to the requirement of underwater all-position welding for drainage cover, simulating the drainage process of typical space position with FLUENT. The structural form of drainage cover and drainage velocity and piping layout is optimized based on the simulation results. Making drain cover according to optimization results to complete drainage experiment.(3) A dry hyperbaric chamber is used to simulate to underwater dry welding environment and for all-position welding experiment. Using the method of numerical fitting to obtain the relationship between welding parameters and position according to the experiment welding parameters of typical location to provide basic data for welding operation of underwater robot.(4) Using the underwater mobile welding robot to carry out the local dry welding experiment to obtain good welding seam.Through the theoretical analysis and simulation and experimental research verify the underwater mobile welding robot can meet the requirements of the all-position welding. Preliminary feasibility with the welding of large steel structure under water.