In: IEICE Trans. on Fundamentals in Electronics, Communications and Computer Science, Vol. 81-A, No. 4, pages 615-625. 1998.
Abstract: A scheduling problems for automatic assembly, planning of task sequence is closely related to resource allocation. However, they have been separately carried out with little interaction in previous work. In assembly planning problem, there are many feasible sequences for one mechanical product. In order to find the best assembly sequence, the cost function for each product has to be decided a priori. But the cost of each task depends on the machine which executes the allocated task, and it becomes difficult to estimate the exact cost of each at planning stage. Moreover, no concurrent operation is taken into account at planning stage. Therefore, the sequence planning and the machine allocation should be considered simultaneously. This paper proposes a new scheduling method in which sequence planning and machine allocation are considered simultaneously. First, a modeling method for an assembly planning including a manufacturing environment is proposed. Secondly, a guideline is proposed to determine the estimate the assembly scheduling. Thirdly, a new search method is proposed. Fourthly, a new technique is proposed which can take into consideration the repetitive process in a manufacturing system so as to improve the calculation time. Finally, numerical experiments for the proposed scheduling algorithm are shown and the effectiveness of the proposed algorithm is verified.
Keywords: assembly scheduling, mechanical assembly, timed Petri nets.
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