Research On Reusable Planning Method For Assembly Path Of Complex Products

Assembly path planning is an important part of assembly process planning,and it is the key link to realize the structure and function of complex products.Based on the review of knowledge representation and reuse of product assembly and path planning reuse,this paper focuses on the research of reusable planning methods of complexed product assembly path.Including the mapping of multi-source assembly information and path reuse degree,the construction of isomorphic space of assembly path planning based on path reuse degree,and the rapid planning of assembly path based on hybrid improved RRT~* algorithm.The proposed method and technology have verified by the application of reusable assembly path planning of complex products such as CNC milling machine.The main contents of this paper are as follows:In the first chapter,the research and application of assembly knowledge representation and reuse technology,assembly path planning technology and path knowledge reusable technology at home and abroad have summarized.Based on the analysis of the research status at home and abroad,the research background,research content and framework of this paper have introduced.In the second chapter,the reusability of assembly path planning has analyzed from assembly task level and assembly process level,and the related factors and implementation methods of the reusability of assembly path planning have pointed out.On this basis,the multi-source assembly information model and Multi-source information model for reusing assembly path of components are constructed.In this paper,a method of non-linear spatial point set mapping of multi-source assembly information under task level constraints is proposed,and the correlation mapping between multi-source assembly information and path reuse degree and the index construction of path reuse degree have realized.Finally,a multi-source information model of assembly path reuse has constructed with NC milling machine as an example.In the third chapter,the configuration space expression of assembly path planning considering prior path has analyzed,and the concept of prior degree has defined and introduced into prior position and pose point representation and prior space construction.The similarity measurement method of multi-source assembly information in nonlinear mapping space is established,and the calculation method of path reuse degree integrating multi-source assembly information is proposed.Based on path reuse degree and multi granularity clustering,cluster reduction of batch parts has realized.The inter cluster bounding box is defined.The reusable assembly configuration space is constructed by the information of inter cluster bounding box.Finally,the numerical control milling machine has taken as an example.The method of building reusable configuration space based on reuse degree has applied and verified.In the fourth chapter,we study the problem of path reuse in isomorphic and heterogeneous space based on random sampling algorithm,and propose a path reuse planning method under heterogeneous constraints.For the reuse of assembly path in isomorphic space,an improved algorithm SR-RRT~* based on RRT~* is proposed.For the reuse of assembly path in heterogeneous space,a DR-RRT~* algorithm based on dynamic backtracking strategy is proposed.Finally,the feasibility and efficiency of the fast planning method of assembly path based on hybrid improved RRT~* algorithm are verified by experiments.In the fifth chapter,the prototype system of reusable assembly path planning for complex products has developed,including Assembly task management module,Part information management module,Reusable configuration space building module and Reusable path planning module.The architecture and main function realization process of the prototype system have introduced.The sixth chapter summarizes the research results of this paper and looks forward to the future work.