Research And Development Of Control System For Commercial Vehicle Fifth Wheels Welding Production Line In Harsh Working Conditions

With the rapid development of Chinese logistics industry and the transportation industry, the semi-trailer has become a major road freight tool. The fifth wheel is the connection device between the semi-trailer and semi-trailer truck, is one of the important semi-trailer parts. It is not only the connecting part of a semi-trailer, but also the safety component. Therefore the implementation of a commercial vehicle fifth wheel welding production line is conducive to realize the mass production and specialized production of fifth wheels, but also conducive to improve the enterprise’s benefit for the fifth wheel production. This effort could also promote the vigorous development of the logistics industry.At present, domestic enterprises have no implementation for commercial vehicle fifth wheels welding production line, single station operation mode is mostly adopted to conduct the fifth wheel welding operation, which means a worker completed all points of welding jobs in a single workstation. So the design and manufacture of fifth wheels welding production line would be the first implementation in our country, and the corresponding control system research and development is also the first time. This requirement originates from the cooperation projects of Y enterprise and Wuhan University of Technology. In order to ensure the stability and maturity of the control system, the paper decided to adopt the PLC whose technology is more mature as the core control component of the welding production line.PLC has high reliability, strong anti-jamming capability, easy operation, and high flexibility, so it is widely used in the field of modern industrial control. As the core component of field control device, PLC is used for the logic control, process control, motion control, data processing and communication network. Fifth wheel welding production line will use flexible design, without changing the hardware wiring and electrical control circuit, you can change the fifth wheel welding process by modifying the corresponding control parameters or change the PLC procedures. Based on full study of the PLC and HMI control technology, in this paper the author has analyzed the welding line layout and welding operation process, and has given the PLC control methods and specific ladder diagram language. The main work of this paper includes the following aspects: 1. The author solved the detailed problems of the PLC and HMI control technology, including PLC’s basic structure, working principle and characteristic. The way that the PLC can be used as a control equipment and the HMI can be used as a host computer will be the control method for fifth wheel welding production line.2. The layout and production cycle time of this welding line and the control operation process for each station are researched and analyzed in detail. Finally, the uses of PLC’s each I/O points and the specific model of the PLC are presented.3. Three control methods of PLC are analyzed. Based on the production line layout and control requirements, it is concluded that the application of PLC distributed control mode. Then the PLC N:N network technology is researched in detail and the HMI will be the host computer of the main station PLC in order to monitor the entire running state of the welding production line.4. The anti-jamming measures, installation and commissioning of the control system are researched, in order to ensure the welding line run well and achieve the desired control requirements.