Path Planning Strategy And Experimental Research Of Multi-layer And Multi-pass Welding Robot For Medium Thick Plate

Medium thick plate is widely used as a building,ship and other large welded structural parts,multi-layer and multi-pass welding is its key technology,the current use of welding robots to achieve automatic welding of medium thick plates has become a hot technical problem,and the automatic planning of welding paths is the premise of welding robots to complete the multi-layer and multi-pass welding of medium and thick plate grooves,due to processing errors,installation errors and other factors,the actual working conditions of the non-standard form of thick plate welding grooves,the multi-layer and multi-pass welding path planning of the thick plate groove puts forward higher requirements.Therefore,this paper carries out theoretical,simulation and experimental research on welding groove weld filling strategy and welding robot motion planning control,realizes the automatic planning of welding path of welding robot,and completes robot automatic welding.The main research contents and work of this paper are as follows:(1)Design multi-layer and multi-pass weld filling strategy for medium thick plate.This paper analyzes groove form and welding condition in multi-layer and multi-pass welding,studies the influence of welding parameters on bead forming area,and establishes the relationship model between bead forming area and welding current and welding speed.For the typical V-shaped groove in multi-layer multi-pass welding of medium thick plates,the custom filling strategy of welding groove is designed on the basis of the research related to the welding groove filling strategy,and the welding bead layout planning of different grooves can be realized without frequent adjustment of welding parameters.(2)Simulation analysis of welding path based on welding pass layout model.The finite element method is used to analyze the multi-layer and multi-pass welding path of medium thick plate.Based on the simulation analysis theory of temperature field and stress field in the welding process,the appropriate welding heat source model is selected.In weld configuration model research based on the analysis of weld bead set in the end of the welding torch position different heat source for the influence of the temperature distribution in the slope mouth,selecting appropriate welding torch location,welding parameters analysis research of the combination of the welding residual stress after the completion of the work under different speed,considering the distribution of residual stress to determine the appropriate welding speed.(3)A motion planning control strategy for multi-layer and multi-pass welding is designed.The motion control model of welding robot is established and the transformation relation between coordinate system and workpiece coordinate system is determined.Combined with the welding pass layout model of typical V-groove,the welding position and pose are planned based on the simulation analysis of welding path,and the welding speed is planned according to the specific conditions of welding path operation.(4)The multi-layer and multi-pass welding experiment platform of welding robot was built for simulation and experiment.According to the actual functional requirements,complete the hardware construction and software design of the experimental platform,simulate and simulate the welding path planned,and complete the automated multi-layer multi-channel welding at the work site to verify the feasibility of actual welding.