Research On The System Of Lifting Appliances Assembly Sequence Planning Based On Extension Case Reasoning

Computer aided assembly process planning is an important research area in assembly process. With the implement of advanced manufacturing technology in lifting appliances enterprise, for the complexity of lifting machinery, how to develop the intelligent system to help to plan lifting appliances assembly process has become one of pivotal problems to be resolved. Aiming at this problem, a mechanism of lifting appliances assembly sequence planning based on case-based reasoning is proposed in this paper. In this mechanism, assembly process planning of sub-assembly and component is chosen as the research object, assembly knowledge’s representation, similarity measurement and adaptation are studied, a prototype system is developed.The main research issues and achievements in this paper are as follows:1. With the current research status of lifting appliances digital assembly process planning, a basic framework for the system is set up. Oracle XML DB is selected as the foundation database of case-base. A module of case-based reasoning based on extensive and another module of retrieving and conflict strategy are designed. A method of perfecting case base is given,2. The correlation function in extension theory is researched. Then the assembly model based on extension theory is established. Then the extension similarity model is built on the basis of extension distance. A new module division method is proposed based on extension relation which is applied on the trolley of double beam bridge carne.3. Aiming at lifting appliances, assembly case representation and organization are researched. After the analysis of the lifting appliances assembly structure feature, index of case base, retrieving and conflict strategy are built for lifting appliances assembly case base to improve the efficiency. A similarity calculation formula based on extension theory is built and a method to calculate the weight of knowledge feature in similarity measurement with the use of Delphi and AHP is proposed.4. Considering about the theory research of lifting appliances assembly sequence planning system, a prototype system, the system of lifting appliances assembly planning based on case-based reasoning, is developed. An integrated system of lifting appliances assembly planning is set-up.Finally, the full text is summed up, and the further study prospect is proposed.