Research On Assembly Sequence Planning And Optimization Method Of Automobile Suspension

With the proposal of "Made in China 2025",the manufacturing industry is gradually turning to intelligent and modular transformation How to plan assembly sequence has become an important issue that restricts the intelligent development of manufacturing industry.In the assembly process,it involves the selection of assembly tools and assembly direction,and it also needs to consider the interference relationship and sequence between parts,which leads to a large amount of cost occupied by assembly in the whole production process.Automobile suspension contains a lot of parts,so the cost occupied by suspension assembly sequence planning is more serious.At present,the suspension assembly of enterprises is mainly based on the experience of engineers,which leads to a long time for suspension assembly sequence planning and the assembly sequence cannot reach the best,resulting in a large waste of resources.In this dissertation,a method of automatic assembly sequence generation and a method of assembly sequence optimization are presented,and the feasibility of suspension assembly sequence is verified by establishing a virtual assembly system.Firstly,the actual data of automobile suspension is measured,and the three-dimensional model of the suspension is established by software,and the information model of the suspension is established according to the three-dimensional model.In the product information model,the name,weight,size,volume,type,connection relation,interference relation and freedom between parts of the suspension are mainly provided.According to the information model,the Dof join correlation diagram is also established,and the connection relation and interference relation of suspension are represented by matrix,which lays a foundation for assembly sequence planningThen,sub-assemblies in suspension are determined according to the degrees of freedom and connection association diagram between parts in assembly information.The components in sub-assemblies are assembled as a whole during assembly,reducing the number of assembly sequence combinations in assembly sequence planning.Based on the sub-assembly division,the suspension is stratified by the connection relationship between the parts or sub-assemblies,the assembly sequence of a part is further obtained by the method of layer assembly,and the assembly sequence of the parts in each layer is determined by the interference matrix.A feasible assembly sequence of suspension can be obtained according to the progressive number of layers,the problem of obtaining assembly sequence by experience was solved.Then to solve the problem of low assembly efficiency,genetic algorithm is used to optimize the generated assembly sequence.Crossover and mutation stages in the algorithm,using the method of crossover and mutation by the layer and select the number of population in genetic algorithm,the three important parameters of heredity and variation,through different parameters selection,determine the optimal parameter value,the fitness function value in the genetic algorithm convergence effect is best,to get the most optimal assembly sequences.Finally through the establishment of virtual Unity3D system,the use of virtual assembly system immersive experience to observe suspension assembly and disassembly process,was built in the system of assembly and assembly information module,can quickly the assembly of components and parts of the assembly information,combined with the assembly information and the disassembling process to verify the feasibility of suspension assembly sequence.