Environmental Engineering Reference
In-Depth Information
The area for intelligent manufacturing systems was born, and research was
conducted in different directions. One of the major approaches was a project
under the intelligent manufacturing systems (IMS) program, called holonic man-
ufacturing systems (Christensen 1994), which settled as a new research area for
manufacturing control. Holonic systems are composed of autonomous, interact-
ing, self-determined entities called
holons
.
The notion was much earlier introduced by Koestler (1967) as a truncation of
the Greek word
holos
, which mean whole. The suffix on that means part, similar
to the notion used for electrons and protons. Thus
holons
of the manufacturing
entities are parts of a whole.
The HMS project was initialized by a prestudy (Christensen 1994), before the
large-scale project was launched in the period from 1995 to 2000. The huge ini-
tiative had more than 30 partners worldwide. Not only did the project focus on
applications, but also three of the seven work packages concentrated on devel-
oping generic technologies for holonic systems, such as system architecture,
generic operation (planning, reconfiguration, communication, etc.), and strate-
gies for resource management. The application-oriented foci were organized in
four work packages concerning manufacturing units, fixtures for assembly, mate-
rial handling (robots, feeders, sensors, etc.), and holomobiles (mobile systems for
transportation, maintenance, etc.).
The project was very successful regarding generic structures of the holons
aimed at low-level, real-time processing. The specification of the holons was
even formally standardized by the International Electrotechnical Commission
(IEC) 61499 series of standards.
The holonic parts came to short in systems requiring higher level of reasoning
(Brennan and Norrie 2001), thus the term of holonic agents was introduced
(Marik and Pechoucek 2001). Software agents encapsulate the holon and provide
higher-level decision logic and reasoning, but also more intelligent mechanisms
to cooperate with other holonic agents.
Generally, agent technologies provide a software engineering approach to ana-
lyze, develop, and implement intelligent manufacturing control for distributed
entities and holons. Whereas the holons were formally specified through the
IEC standards, agent-based manufacturing control still lacks from having formal
standards, even though various attempts have been taken — YAMS (Yet Another
Manufacturing System) by Parunak (1987) or MASCADA (Br uckner et al. 1998)
among others.
Research on manufacturing and material handling systems has gradually
moved from a monolithic control toward a decentralized, distributed, and — most
recently — agent-based approach, but only a few real systems have adopted
the shop-floor models. Production 2000
) is an exception, and is
generally known as the first agent-based manufacturing system that has moved
from research into real production. P2000
+
(P2000
+
was installed at Daimler to produce
cylinders. The objectives of the project were to develop a robust and flexible
+
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