wilamowski-b-m-irwin-j-d-industrial-communication-systems-2011

Industrial Agent Technology 16-7
functionalities of the MES. Generally speaking, a mediator is a supervisory agent that temporarily or
permanently takes a role of decision making and combines certain resources into a virtual cluster to
solve certain problems. However, please keep in mind that MetaMorph is meant to be an integration
tool for other systems rather than a complete solution.
Similar agent-based architectures with slightly different implementation focuses are Autonomous Agents
at Rock Island Arsenal (AARIA) (cf. [9]), manufacturing control systems capable of managing production
change and disturbances (MASCADA) (cf. [26]), and ADAptive holonic COntrol aRchitecture (ADACOR)
for distributed manufacturing systems (cf. [38]). Architectures like Advanced Fractal Companies Use
Information Supply Chain (ADRENALIN, cf. [25]) consider agent-based resource brokering functionality
enabling a decentralized manufacturing order navigation based on local optimization strategies.
In contrast to that, Plant Automation Based on Distributed Systems (PABADIS, cf. http://www.unimagdeburg.de/iaf/cvs/pabadis/,
[8]) and its follow-up PABADIS’PROMISE (PABADIS-based Product-
Oriented Manufacturing Systems for Reconfigurable Enterprises, cf. http://www.pabadis-promise.org/)
provide agent-based architectures that cover the whole automation pyramid but with the primary focus
on distributed MES (cf. [25]).
Due to the fact that different MES solutions usually focus on a specific area of implementation, for
example, scheduling, customer support, resource utilization, or system integration, they often cannot be
compared. For this article, the focus is set on systems that cover the complete manufacturing process,
that is, on systems that cover the vertical integration of all layers of the automation pyramid from the
ERP down to the field control level. More specifically, the focus is on the HMS-based system PROSA
(and some aspects of MetaMorph) and on the MAS-based systems PABADIS and PABADIS’PROMISE.
Although the above-mentioned solutions differ in their approaches, they exhibit in their concepts
common patterns in approaching MES implementations. The main pattern is the division of decision
making into two main entities: orders and resources. The first one represents the customers and the
upper layers of systems that provide a MES with the orders on what to do (in practice a set of steps how
to produce a product) that are then distributed into the agent community. While different solutions differ
in the order handling concepts, the second entity—representing the resources on the shop floor that
execute particular operations—has similar characteristics in all solutions.
In addition to the main patterns, all solutions provide supervising entities that show how far each
concept deviated from conventional centralized approaches (see Figure 16.2). And last but not least, in
order to glue the agents together, each architecture provides certain brokering functionality—as a centralized
entity or via a hierarchy of objects, either static or dynamic.
Enterprise resource planning
Stuff holon
Plant management
agent
Order agent
supervisor
Resource agent
supervisor
Order holon
Product
holon
Product
agent
Look up
service
Order agent
Ability
broker
Resource
holon
PROSA
Residential
agent
PABADIS
Resource
agent
PABADIS
PROMISE
Field control
FIGURE 16.2
General patterns in distributed MES.
© 2011 by Taylor and Francis Group, LLC