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Ch43-I044963.fm Page 207 Tuesday, August 1, 2006 3:58 PM
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GENETIC ALGORITHM BASED REACTIVE
SCHEDULING IN MANUFACTURING SYSTEM
-ADVANCED CROSSOVER METHOD FOR
TARDINESS MINIMIZATION PROBLEMS -

J
2
2
1
T. Sakaguchi , Y. Tanimizu , K. Harada , K. Iwamura and N. Sugimura 2
'Graduate School of Science and Technology, Kobe University,
1-1 Rokkodai, Nada-ku, Kobe 657-8501, JAPAN
2
Graduate School of Engineering, Osaka Prefecture University,
1-1 Gakuen-cho, Sakai, Osaka 599-8531, JAPAN
Manufacturing Engineering Service Dev., Toyota Motor Corporation,
1 Shimoyama, Uchikoshi, Miyoshi-cho, Nishikamo-gun, Aichi 470-0213, JAPAN

ABSTRACT
Recently, flexible scheduling systems are required to cope with dynamic changes of market
requirements and manufacturing environments. A reactive scheduling method based on Genetic
Algorithm (GA) was proposed, in the previous research, in order to improve an initial production
schedule delayed due to unscheduled disruptions, such as delays of manufacturing processes. The
objective of the research is to propose a new GA based reactive scheduling method for tardiness
minimization scheduling problems, aiming at improving the disturbed production schedule efficiently
and generating suitable production schedules faster than the previous reactive scheduling method. A
prototype of reactive scheduling system is developed and applied to computational experiments.

KEYWORDS

Scheduling, Genetic algorithm, Flexible system, Tardiness of job, Recovery, Object-oriented

INTRODUCTION
Unscheduled disruptions, such as delays of manufacturing processes, addition of emergent jobs and
failures in manufacturing equipment, often occur in the actual manufacturing systems. However, most
of the traditional scheduling researches assume that manufacturing environments are well stabilized.
The manufacturing system becomes impossible to satisfy the constraints on the due dates and the
make-span, when the initial schedules are delayed due to the unscheduled disruptions.
The reactive scheduling method (Smith 1995) is defined here as the method that modifies and
improves the predetermined initial production schedules, when some unscheduled disruptions of