Research On Key Technologies Of Three-dimensional Assembly Process Planning System

With the rapid development of computer technology,the traditional mechanical assembly technology can not meet the existing requirements of the development of productive power. Combined with the computer,the new type of assembly process planning technology is popular among large number of manufacturing enterprises for its low-cost and high-efficiency. Based on the research of three-dimensional assembly process planning system in recent years, the state of art of the assembly process and interference testing is studied in depth in the thesis.The thesis presents a three-dimensional assembly process planning system (KMAPS) by hierarchical organizational framework and the functional system. The process of technology and main functional modules are introduced.A new type of interference checking algorithm based on the bounding box of hierarchical decomposition and recursive calculation is proposed against the existing interference checking algorithm. The algorithm essentially combines the efficiency of bounding box and the stringency of precise collision detection. First, the algorithm checks the interference between the two assembly parts with bounding box algorithm and removes the parts without interference. Second,the remaining parts of the assembly components are decomposed. Third,the above two steps repeat until each assembly parts is the single part. At last, the precise collision detection algorithm is called to conclude the interference testing process. The algorithm is achieved on the interactive platform of ACIS/HOOPS.The assembly process simulation module of KMAPS takes account of assembly tool for the purpose of better simulation to actual assembly process. The traditional principles are described of assembly process simulation and the matrix knowledge such as the translation movement, rotary movement and composite movement of sub-assembly is discussed. The importation of assembly tool, the definition of positional information, the match of positional information, the access of assembly path, and the assembly simulation of assembly tool are introduced in view of the tools in assembly simulation. Information flow chart and the attainable steps are explained in accordance with the simulation module on the basis of assembly tools. By analyzing the assembly process planning of a gearbox with the interference algorithm and assembly process simulation which mentioned above the effectiveness of the system is validated.