Research On Virtual Assembly Sequence Planning Using Case-based Reasoning

The assembly sequence planning is an important link of the product production, and the assembly sequence optimization can not only shorten the development cycle of the products, to reduce the production cost, but also can improve the reliability of the product. Therefore, the research on the assembly sequence planning has very important practical significance and application value.With the emergence of virtual assembly technology, the traditional assembly technology has a new model, which is, simulating the assembly process in a virtual environment. The virtual assembly can reduce the physical model making, shorten the product production and operators training cycle, reduce development risks and cost, improve assembly quality and efficiency. Among them, the sequence planning is an important link and key technology of virtual assembly. The research purpose in this paper is to provide feasible assembly sequences support for the virtual assembly system for improving the efficiency of assembly planning.This paper first introduced the domestic and foreign research situation about the research on the assembly sequence planning, compared the advantages and disadvantages of various methods solved the assembly sequence planning. On the basis of the above, the thought of knowledge reuse is decided to use, the case based reasoning technology is tried to solve the assembly sequence planning. After the study on CBR model, combined with the application of assembly the solutions to the three key problems of case reasoning technology are given. The main research works are:(1) Use the rank correlation assembly model to show the assembly information, and realize the information automatic acquisition with secondary development model in Pro/ENGINEER system.(2) Propose two similar measures for finding similar cases and for finding corresponding relationship between parts in two similar cases. After get the similar case, correct the similar case with rule and existing knowledge based method.(3) The traditional traverse search has disadvantages such as blind judgment, large amount of calculation because of no control strategy. In order to improve the efficiency, put forward a kind of case retrieval method based on the spectral clustering. The experiment results show that this method can improve the efficiency of searching in premise of guaranteeing retrieval accuracy.(4) Develop an assembly sequence planning system using case based reasoning technology, which can solve simple assembly sequence planning problems.