The term "holon" was ?rst introduced by Koestler (Koestler, 1967) to c-
ture the idea that both biological and social structures consisted of
entities that were part of a larger whole, while being self-contained
entities in their own right. These entities were called holons and the
structures that they form werecalled holarchies. Inthisbook,
wepresentaconceptualmodelforholonic manufacturing execution and then use
this model to develop two implem- tations for an execution system for an
industrial strength robotic assembly cell. The model is based on the
experience that we have gained in developing a number of agent-based
execution systems over the past 10 years.
Manufacturingexecutionisthatactivitywhichisconcernedwiththem- agement of
actual manufacturing tasks. It involves interaction with device
controllers, but it is conceptually separate from manufacturing control.
The applicability of the holonic concept to manufacturing was ?rst noted
by Suda (Suda, 1990) and this led to the formation of the Holonic
Manufacturing Systems project in 1993 (HMS Consortium, 2001). The HMS
project was conducted under the auspices of the Intelligent
Manufacturing Systems (IMS) program (IMS, 2005) and remains of the
largest of the IMS projects to have been undertaken. The HMS project
spanned three separate phases, ending in 2004. In addition, a signi?cant
amount of work (including the work described in this book) was conducted
outside the HMS project. Conceptually, holons are similar to agents.
