| Summary: | 碩士 === 國立台灣工業技術學院 === 管理技術研究所 === 85 === Shop floor controller plays an important role in the integration
of the information flow in a computer integrated manufacturing
system. Hierarchical control structure has been applied widely
in industries. One of the major argument about this framework is
that the flow of the information might be concentrated in the
central controller and hence might cause it too busy to handle
certain abnormal conditions. Recently, modified hierarchical
control frameworks have addressed many attentions. Due to the
autonomous capabilities added to the local controllers, certain
functions carried out by the central controller in the
hierarchical structure are performed by the local controller.
Therefore, the information flow should not be concentrated in
the higher level central controller. However, most of the
researchers only illustrated this phenomenon, very few
quantitative analyses support this argument. In this research, a
Colored Stochastic Petri Nets (CSPN) model was developed to
describe the information flow in a modified hierarchical
structure. The developed model was simulated by using a
commercial package ALPHA/Sim. The experimental results showed
that only less than half of the capacity of the central
controller has been utilized. These results also proved that
that modified structure can improve the traffic condition about
the information flow in the central controller.
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