Research On The Two-sided U-type Assembly Line Balancing Problem Based On Improved Ant Colony Algorithm

At the beginning of the 20 th century,the assembly line was born,which increased the production efficiency of Ford’s workshop to more than 8 times that of the original,and the automobile market developed rapidly.In the 1980 s,the rapid popularization of the Toyota Production System in Japan prompted Japan to surpass the United States as the world’s largest automobile manufacturing country.The concept of lean production has gradually become popular,the lean production method has been widely practiced around the world,and the role of the assembly line in production has become more and more important.As the last link in the production process,assembly is the most important place to restrict output and improve production efficiency.Scholars in the field have conducted in-depth research on assembly line design and its balancing problem.Stright assembly line is the earliest form of assembly line.Later,assembly lines with different layout modes such as U-shape,two-sided and two-sided U-shape appeared.The biggest feature of U-shaped assembly line is high flexibility,which can adjust production in time according to the changes of external environment.It is the product of lean production;Two-sided assembly lines are mostly used in the production process of large products.Workers can be arranged on both sides of the assembly line,which greatly shortens the length of the assembly line.The two-sided U-shape assembly line is a combination of the two.The ordinary two-sided lines are arranged in a "U-shape" layout,which not only retains the characteristics of parallel assembly of two-sided assembly lines,but also can share fixtures and reduce time waste;It also has the advantages of cross workstation of U-shape assembly lines,and the visibility of the assembly line is stronger and more flexible.This paper classifies the domestic and foreign literature of two-sided assembly line,ant colony algorithm and two-sided U-shape assembly line balancing problem,studies the development process of assembly line,ant colony algorithm to solve assembly line balancing problem,classical examples of assembly line balance,etc.,and summarizes the research status at home and abroad.This paper summarizes the relevant theories of two-sided U-shape assembly line,including the design,balancing problem and balance complexity.Considering the fusion characteristics of left and right partitions and cross workstations of two-sided Ushape assembly line,taking the minimum number of assembly line positions and workstations as the primary goal and the minimum smoothing index as the secondary goal,a multi-objective mathematical model of type-Ⅰ two-sided U-shape assembly line balancing problem（TUALBP-Ⅰ）is established.A multi-level priority rule heuristic algorithm is proposed,which determines the candidate tasks based on four-level constraints.The priority value rule is used to select tasks and assign tasks.20 small-scale classical examples are calculated to verify the effectiveness of the heuristic rules.The principle and solving steps of the improved ant colony algorithm are introduced.40 groups of classical examples are calculated under the left and right layout respectively.The calculation results are compared with the results of particle swarm optimization algorithm and two-sided straight line respectively,analyzing the evaluation indexes of the examples,to verify the feasibility of the improved ant colony algorithm.