Development And Study Of Control System For Automated Seam Welder

The fuel tank of the car is an important component to ensure the car’s smooth operation and fuel supplies, whose main function is to storage the fuel. The leak-rate is an important index to measure the safety and quality of the fuel tank. As welding is the key process to ensure the tightness of the fuel tank and to prevent the leak, so seam welder is one of the key equipments for the welding of fuel tank. Nowadays, most domestic seam welders are equal to the automated welding process, while the workers have to deliver the fuel tanks manually, so they are mostly semi-automated products. With these seam welders welding fuel tanks, poor welding environment and low efficiency results, and the quality of welding can hardly be ensured. In a word, the development and research of a automated seam welder have a very important practical significance in improving the productivity and ensuring the quality of welding.With the research of the automated seam welder and the analysis of its mechanical structure and operational principle, a welding platform for the welding of fuel tank is developed, which can achieve automated welding of fuel tank by cooperating with the old semi-automated seam welder.According to the welding process of the fuel tank and the property of the old seam welder, the whole mechanical structure of the automated seam welder is developed, which mainly includes the welding platform system and seam welder system. The welding platform system composes of the transmission system of the three axes, X, Y, C, while the seam welder system basically follow the old one, just taking over some welding signals, so as to cooperate with the welding platform system to achieve automated welding of fuel tank.Based on the mechanical structure and operational principle of the automated seam welder, the overall solution of the control system is designed. In addition, the hardware structure is proposed to meet the requirement of the former control system. Then the main hardware, mainly including PLC, servo system, touch-screen are selected, and the input and output points of PLC and the pins of servo system are reasonably planned. Moreover, for the sake of the layout and maintenance of the circuit, the electric system of the automated seam welder is designed, which is mainly made up of the main circuit, the circuit of servo system for X,Y,C axes, the circuit of servo system for axis, the circuit of PLC input, the circuit of PLC output and so on. In accordance with the control requirements of the automated seam welder, the software design of it is completed, in which PLC corresponds with touch-screen and upper computer via two serial ports to change data. At the same time, the programs of touch-screen and upper computer are accomplished, achieving storage, selection and invocation of production data in touch-screen, and the automatic assignment of the instruction and the automatic storage and inquiry of the welding information of the fuel tank. Finally, the PLC program is designed according to modular thought.By means of development and research of the automated seam welder, automated welding of fuel tank is achieved, in which the servo motor adopts torque follow-up mode to match the line speed of the electrode of the seam-welder the line segment, and it accomplishes arc transition through the data sampling interpolation and triaxial linkage in arc segment welding. Also the workers can friendly operate the seam welder through touch-screen, and remote monitoring and operation and retrospect of the welding information of fuel will be in convenient access via upper computer. Of course, the work environment, the welding efficiency and the welding quality are improved. Up to now, the automated seam welder has been installed and debugged, and it runs so well that the company accepts it without doubt.