Development Of Experimental Underwater Welding Robot And Research Of Underwater Welding Technology

With the increasing depletion of land resources,the sight of the human is gradually turned toward the ocean.All kinds of marine structures are emerging as marine resources exploitation has become a global strategy.Due to poor working environment and complex load,marine structures are easily damaged while its installation and maintenance are inseparable from welding as well as underwater welding.The appropriately use utilization of underwater welding technology can reduce operating costs of offshore structures meanwhile shorten the maintenance cycle,therefore,strengthening its research and applications has an enormous significance to the development of the marine industry as well as the exploitation of marine energy.Currently,the implementation of underwater welding is mainly relying on the operation of underwater divers.A tiny minority of welding operation with application of automatic and intelligent technology still require divers assisted,leading to low welding efficiency,high cost and high risk.The certainly tendency of combining underwater robots with underwater welding technology determines the future direction of underwater welding,underwater welding robot will be the focus study with respect to underwater welding subjects.This paper aims at developing an underwater robot which can be applied to pool test performing underwater welding,engaging in a series of research work.On one hand,we try to design and manufacture underwater welding robot test prototype,on the other hand,we research welding process which is suitable for underwater welding robot.Firstly,the development of underwater welding robot test prototype can be divided into five parts of the detailed design,namely the body framework,buoyancy modules,propulsion systems,automatic underwater welding agency and underwater pressure capsule.Corresponding to five portion respectively,we design and manufacture PVC plastic and aluminum open body frame,adjustable buoyancy tube buoyancy modules,all closed magnetic coupling thruster combined propulsion system with thruster made by 3D printing of ABS material,high strength acrylic(PMMA)Pressure capsule,ball screw linear modules welded body,and at the same time,utilizing through the method of theoretical analysis and numerical simulation to conduct theoretical calculation and verification to all systems.After the assembly and debugging of the underwater welding robot,a plenty of underwater welding tests with employing plasma arc welding process are carried out,getting a good welding parameters and weld joint shape.Finally,the analysis of the weld shape and weld quality is conducted from the perspective of macro as well as micro,and pulling test further verify the good welding quality,which can be used for reference for further study of underwater welding robot.