| With the fierce competition in domestic and international market, the increasing of laborcosts and environmental requirement, the shortage of skilled welding workers, and theincreasing requirement for welding quality and productivity, the welding automationequipment market is entering into the quick developing stage. Having the advantages of highspeed, great efficiency and high automation, the double wire welding robotics has become oneof hot topics in the field of welding automation. At present, general welding system is widelyapplied in the double wire welding robot in the world. In the process of high speed doublewire welding, due to the strong interaction between two arcs; it’s hard for welding system tomake accurate and quick response to the dynamic process of welding arcs. And the range ofparameter adjustment is too narrow to control the thermal input in the welding processprecisely. So the desired practical result is difficult to be achieved.Based on the base ofexisting research study, this paper systematically studies the distributed control, DSC (digitalsignal controller), soft switching inverter technology, and the stability of power-arc systemunder the digital condition, and successfully develops a high efficient two wire arc weldingrobotic system of waveform control type.Chapter one analyzes and summaries related research achievement in this field includingkey technologies for welding robot, technologies for double wire welding equipment andwaveform control, etc. Base on that, this paper develops a general solution to existingproblems—the waveform control type double wire arc welding robotic system based ondistributed structure.Chapter two designs the overall structure of waveform control double wire arc weldingrobotic system. By analyzing the definition and structure of distributed control, the overallstructure of distributed waveform control type two wire arc welding robot is constructed. Torealize the coordinating control of the units in the system, we choose the GSK’s RB-08robotand GSK-RC robot control cabinet, design wire feeding machine, choose the CAN bus as thecommunication bus of welding site and design communication protocol to realize the coordinating control of the units.Chapter three discusses the digital welding power sources based on DSC. We analyze thegeneral structure, and design the main circuit based on limited bipolar soft switching topologyso the high speed switch of electricity become possible. And we build the CNC(ComputerNumerical Control) system for welding power source with the high speed DSCmicroprocessor STM32F405as its core. Besides we design digital panel based onSTM32F405to realize the digitization of human-computer interaction.Chapter four studies the stability of power-arc system under the condition ofdigitalization and reverse change. We analyze the feature of single/double wire welding arcand welding, and puts forward an arc length strategy based on changing output characteristicsof welding power source. Along with that, we designed the median current waveform controlstrategy to improve the controllability of the molten drop transition.Chapter five studies the welding technology for single waveform control arc weldingrobot. We structured experiment platform and weleding test has been carried out. Theeffectiveness of the changing output characteristics of arc length control strategy and thedesigned drop control median current waveform have been tested and researched.The effectand law of the main welding parameter has also been explored.Chapter six studies the double welding technology.Based on the result of the single wirewelding test, the effectiveness of the changing output characteristics of arc length controlstrategy and the designed drop control median current waveform in double wire weldingprocess have been tested and researched.The effect and law of peak current,middlecurrent,welding frequency and welding speed in double wire welding have been explore. |
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