| Nowadays, mixed-model assembly line (MMAL) has become increasingly popular as a form of production organization in the manufacturing industry because of its superiority on the response to the multi-variety and small-batch market demand. However, compared with the simple assembly line, it seems much more complicated.This paper summarized the previous studies, and researched on the mixed-model assem-bly line balancing problem (MMALBP) of a shelter company. Firstly, the balancing problem is divided into two categories according to its characteristics:(1) type Ⅱ balancing problem of shelter assembly line with same precedence, SAL-SP-Ⅱ;(2) type I balancing problem of she-lter assembly line with conflict precedence, SAL-CP-I.SAL-SP-Ⅱ balancing problem is similar to the previous MMALB problem with the same precedence of common tasks between different products, so its mathematical model is similar to the previous studies. The difference is that some unique constraints are added to the model according to the characteristics of the problem.Then, a dual-population genetic algorithm with the exploration population and the exploitation population is designed and applied on a pratic-al example. The results showed great improvement compared to the current status, indicated the validity of the model and algorithm.While SAL-CP-Ⅰ balancing problem is different from the previous MMALB problem with conflict precedence of the common tasks between different products. The problem is how some common tasks can be duplicated under the assumption.Model is subjected to the constraint of precedence relationships, assignment and cycle time, and the objective function combined the efficiency with the difference of the smoothing index which can effectively dis-tinguish the same number of workstations solutions. Then, an ant colony algorithm with hybr-id search mechanism is designed to solve the problem. Finally, the mathematical models are illustrated and validated by means of a numerical illustration. |
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