Research Of Welding-assembly Fixture Of BIW And The Key Components Design

The topic comes from an industrial project "the development of the unit key technology of flexible, automatic assembly-clamping system of the BIW", entrusted by an industrial firm. The purpose of this research is to complete the design of a fixture with the function of fast positioning and clamping the workpieces for welding, to device an automatic electric-pneumatic hybrid control system for the automatic welding-assembly system of the BIW and completing the design and analysis of functional characteristics of the key pneumatic components. The research has great significance in improving the precision, quality and efficiency of the Welding-assembly of BIW, enhancing the working stability of the Welding-assembly fixture in harsh environments and saving the investment. Moreover, it has great significance in improving automation and flexibility of the Welding-assembly fixture and promoting our country’s independently development level of the automobile process equipment.The thesis take the inside assembly of the right rear door of the BIW as the instance of the research. Chapter2summarized the datum reference principle of the welding-assembly fixture of BIW and proposed the basic requirements, steps and the assessment basis. Chapter3analyzed the basic structure of the inside plate assembly of the door’s, proposed the assembly process and RPS points distribution, designed the basic clamping and positioning components of its RPS points and its overall structure with CATIA software. In Chapter4, according to the Welding-assembly process and the designed fixture structure, the basic principle of automatic control system and the scheme were determined. The Inline electrical control module and pneumatic control circuit system which respectively bases on the INTERBUS bus system and Valve-Island were designed. Chapter5, According to the principle of connecting rod slide block mechanism, the structure of the integrated pneumatic clamping device is designed, establishing the mathematical model of its working characteristics with theoretical mechanics, and applying MATLAB software to the working characteristics of mathematical model for numerical simulation analysis. In the end, we complete the design of the pneumatic positioning device and the integrated position sensing device which being applied to the two pneumatic devices above.In the thesis, the fixture structure of research and design uses the new type pneumatic components, its control system uses the modular structure of the bus control system, which is beneficial to improve the automation and flexibility of the fixture and enhance the stability of the system. Two new key pneumatic components have superior performance, and have a wide range of applications in the field of the welding-assembly fixture. It has certain innovation.The work present in the thesis is the basic work of the unit key technology of flexible, automatic assembly-clamping system of the BIW. It will play a better role in assembly-clamping production line to further integrate the control technology of the assembly-clamping fixture with the robot control technology. The key pneumatic components which have been designed should be carried out further research on the performance of stability and reliability under the high intensity working conditions.