Optimization of a flow shop system of initially controllable machines
Date
2008-12-22Source Title
IEEE Transactions on Automatic Control
Print ISSN
0018-9286
Electronic ISSN
1558-2256
Publisher
IEEE Institute of Electrical and Electronics Engineers
Volume
53
Issue
11
Pages
2665 - 2668
Language
English
Type
ArticleItem Usage Stats
158
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Abstract
We consider an optimization problem for deterministic flow
shop systems of traditional machines with service costs penalizing small
service times. A regular completion-time cost is also included so as to complete
jobs as early as possible. The service times are assumed to be initially
controllable, i.e., they are set at the startup time. Assuming convexity of the
cost functions, we formulate a convex optimization problem after linearization
of the max constraints. The numeric solution of this problem demands
a large memory limiting the solvable system sizes. In order to relieve the
memory bottleneck, some waiting characteristics of jobs served in fixed-service-
time flow shop systems are exploited to result in a simpler equivalent
convex optimization problem. These characteristics and the benefit of CNC
machines are demonstrated in a numerical example.We also show that the
simplifications result in significant improvements in solvable system sizes
and solution times.