Research On Key Technology Of Digital Assembly Process Planning For Marine Diesel Engine

With the development of integrated and innovative engineering application technology which integrates information technology and manufacturing equipment,the research and application level of digital assembly process planning technology has been continuously improved.However,due to the particularity of research objects and the comprehensiveness of technical requirements,a digital assembly process planning system for marine diesel engines has not been developed at present.Therefore,in order to improve the level of digital assembly process planning for marine diesel engines,this thesis studies assembly information modeling,assembly sequence planning and assembly path of the key technologies of digital assembly process planning according to the actual situation of the assembly manufacturing process of related products and the actual needs of relevant enterprises.The main research work is as follows:(1)On the basis of overall analysis of the implementation process of assembly information modeling technology,assembly sequence planning technology and assembly path planning technology,the overall framework of key technologies of assembly process planning for marine diesel engine is established.By analyzing the data requirements in the process of assembly process planning,an assembly information model containing all the requirements information is constructed,which is the only data source in the process of digital assembly process planning.(2)Aiming at the requirement of hierarchical assembly relation information in the process of solving hierarchical assembly sequence,the automatic generation method of hierarchical assembly relation matrix is presented.On the basis of constructing assembly fitness evaluation function,the traditional ant colony algorithm is improved,a new ant local parts selection function and path pheromone updating strategy are constructed,and the optimal assembly sequence solving rules are given.Finally,the validity of the algorithm is verified by an example comparison.(3)Aiming at the requirement of dynamic interference checking technology in assembly path planning,a rough interference checking method based on axially extended bounding box and a precise interference checking method based on entity sweep are proposed.According to the idea of "disassembly can be assembled",the assembly path can be retrieved by planning disassembly path,and on this basis,the method of separating parts from assemblies,the improved RRT algorithm for obstacle avoidance motion planning in the exploration space and path optimization method are proposed.Finally,the feasibility of the path planning method is verified by an example.(4)According to the actual requirements of an enterprise,the assembly process planning(key technology)and simulation system for marine diesel engine is developed,and the functions of digital assembly information modeling,assembly sequence planning,assembly path planning and assembly process simulation are realized.The practicability of the system is verified by an example.