Papers by Keyword: Compliant Assembly

Abstract: This paper proposes a genetic algorithm to generate and optimize assembly sequences for compliant assemblies. An assembly modeling is presented to describe the geometry of the assembly, which includes three sets of parts, relationships and joints among the parts. Based on the assembly modeling, an assembly sequence is denoted as an individual, which is assigned an evaluation function that consists of the fitness and constraint functions. The fitness function is used to evaluate feasible sequences; in addition, the constraint function is employed to evolve unfeasible sequences. The genetic algorithm starts with a randomly initial population of chromosomes, evolves new populations by using reproduction, crossover and mutation operations, and terminates until acceptable sequences output. Finally an auto-body side assembly is used to illustrate the algorithm of assembly sequence generation and optimization.

Abstract: Dimensional tolerance is an important factor for the geometry quality of products. The stiffness matrices of sheet metal components are usually not variational during the process of tolerance analysis; however, material properties of the compliant parts may change in volume production. The variation of the part thickness changes the part stiffness matrix so that the sensitivity matrix is different from that of the assembly with nominal thickness. The paper proposes an improved sensitivity matrix between the incoming part variation and the assembly variation for the assembly with thickness variation. Moreover, the orthogonal design is used to judge the importance of part and thickness variation for the assembly deviation. The proposed method is illustrated through a case study and the results show that the thickness variation influences the relationship between the part variation and the assembly variation. In addition, part variation plays a more important role to assembly variation than the thickness deviation does according to the orthogonal design.

Abstract: A particle swarm algorithm is proposed to generate optimal assembly sequences for compliant assemblies. Firstly, the liaison graph and the adjacency matrix describe the geometry of the compliant assemblies. An assembly sequence is represented by a character string, whose length is the number of all parts. The conceptual tolerance analysis is used to evaluate feasible sequences. Thereafter, the particle swarm algorithm is presented to generate assembly sequences, in which the elite ratio is applied to improve optimization results. Finally a fender assembly is used to illustrate the algorithm of assembly sequence generation and optimization.