
Tom Shelley reports on a radical approach to
manufacturing and management where each order, part and component
is responsibly intelligent.
In systems being trialled and developed, every order, product,
assembly, and machine is associated with its own intelligent
agent, able to communicate and negotiate with others to obtain
best solutions.
Products can find the most appropriate machines to make them, and
reach them by the best route, quickly adapting to the break down
of trucks or conveyors, or new machines suddenly coming online.
First real world applications all seem to be in defence, but
commercial blue chip commercial customers are close behind,
looking for ways to avoid the logjams and software configuration
delays that bedevil conventional supply chain and manufacturing
management processes.
The idea of components and machines being associated with
intelligent 'agents' - some people call them 'holons' - has been
researched for some time. The ancestor of all agents is named
Eliza, born at MIT in 1966 thanks to Professor Joseph Weizenbaum.
Written in only a couple of hundred lines of code, she was
created in order to simulate a conversation between a patient and
a Rogerian psychotherapist. In 1977, Carl Hewitt, also at MIT,
proposed the concept of an agent with autonomous behaviour, able
to answer requests from other agents. Much of the subsequent
development has been driven by the US and UK military, seeking
ways to ensure that swarms of unmanned aerial vehicles achieve
their objectives, even when some are destroyed or damaged, and to
improve the realism of simulated battle and the management of
real battles.
In the commercial field, a component or whole car that is to be
painted blue can be associated with a piece of software that
knows this. The software agent will negotiate with conveyors and
paint shops to send the item to a paint shop that can do blue, by
the shortest and most economic route. Should a conveyor break
down, or the paint shop run out of blue paint, the component can
negotiate an arrangement with a new paint shop and alternative
conveyors, but will inform all the other components about the
problem, according to a subscriber list of agents that 'need to
know'.
Current state of the art has just been revealed at a workshop in
Cambridge. "Intelligent Agents in Industrial Control"
was held at the Centre for Distributed Automation and Control
(CDAC), part of the University of Cambridge Institute for
Manufacturing. Dr Duncan McFarlane, director of the Centre,
presided over the proceedings and explained some of the
advantages of an agent approach.
He considered that the present hierarchical approach to
manufacturing and production is too restrictive in the event of
disruptions. If an individual machine goes out of service, or a
new one is installed in a conventional environment, modifications
have to be made to software in planning, scheduling and
manufacturing order layers. With an agent based approach, in what
he calls, a Holonic Manufacturing System, new pieces of equipment
just have to be installed in a 'Plug and Play' manner, after
which the whole system will find them and make use of them. He
proposes that a software agent be assigned to each order, machine
(resource) and physical product. The agent and the physical item
it is associated with is called a 'holon' - an autonomous but
integratable entity. The order holon negotiates with resource
holons to generate a product holon, which comprises the product
itself, information about the product required and the software
agent responsible for getting the product made. In the event of
broken resource, it renegotiates with the other resources to
still get itself made.
Professor Vladimir Marik, managing director of the Rockwell
Automation Research Center in Prague, told Eureka that Europe is
well ahead of the US in implementing agents in commercial supply
chains and manufacturing. Much of the best work, apparently, is
presently being undertaken in the UK.
Professor Marik described simulated manufacturing systems based
on agents written in JADE, Java Agent DEvelopment framework,
developed by Telecom Italia Labs. However, he also happened to
mention that Rockwell had a demonstration agent based system
running in the US, to improve the fault tolerance of weapons
cooling systems on one of the US Navy's aircraft carriers.
Written with C++ as its core language, it comprises 116 agents
running on five Rockwell ControlLogix and one FlexLogix
controllers. While the C++ software evidently works, moving to
Java will allow the software to run in less memory space and make
use of established libraries and web enabled links to ERP
systems. Java is also unaffected by operating systems, or
operating system versioning. Professor Marik told Eureka that
commercial customers were presently "considering"
taking up the Rockwell version of the technology but declined to
give details.
In the manufacturing arena, software obviously cannot run on
individual components being made, so it has to be closely
associated with them. This brings together the development of
agents, and the accurate recognition of individual components at
all stages as they progress through a manufacturing process
and/or supply chain.
Based within CDAC is the European research arm of the Auto-ID
Center, founded in 1999. The Center is a partnership between more
than 50 global companies plus the University of Cambridge, MIT,
the University of Adelaide, St Gallen University in Switzerland,
Keio University in Japan and Fudan University in China. Its aim
is to develop a standardised technology based on very low cost
RFID, Radio Frequency IDentification. RFID was first conceived by
Harry Stockman in the US in 1948, but it was not until the 1970s
that technology developed to the point that it became
commercially feasible. The Auto ID Center has aggressively driven
down the price of RFID tags. Antennae are now generally printed
on flexible circuit boards, and developments by companies such as
Plastic Logic, which include the ink jet printing of associated
electronic circuitry, should reduce tag costs to a few pence (or
cents).
Auto-ID has a standardised 96 bit key or Electronic Product Code,
that includes version number, manufacturer, serial number and/or
product type. CDAC has set up a demonstration robotic warehouse
cell with support from Gillette, Omron, Fanuc and Agent Oriented
Software that uses Auto-ID and agent technology to select groups
of products and load them into boxes for delivery. The agent
technology allows the system to immediately adapt itself to jams
and breakdowns, and also to prioritise deliveries so as to
maximise profits.
Honeywell has been undertaking research into using agents for
dynamic supply chain management. According to Technology Director
Andrew Ogden-Swift, agents can be situated at all nodes in the
chain. Those attached to suppliers are concerned with what
suppliers can do, while those attached to customers relate to
priorities - who will accept late deliveries with what penalties
- and profits.
Ogden Smith also explained that his company, and others engaged
in process control, while not using agents, are already moving
towards something very similar, but from a different direction.
Model based optimising controllers of one kind and another are
widely used in the process industries, particularly in oil
refineries. In boiler systems, multiple controllers on separate
process units are co-ordinated by a multi-unit optimiser, which
means that the individual units are to some extent autonomous,
and interact with each other, even if they do not negotiate with
each other directly.
Apart from the supply chain management project, most of
Honeywell's agent development projects seem to be funded by
DARPA, the US Defense Advanced Research Projects Agency. A number
of these are battle management related. These have relevance to
business because while oil companies may not physically destroy
each other's installations, they do do their best to destroy
competitor businesses by other means.
With UAVs, or as Dr Jeremy Baxter of Qinetiq explained, with
tanks, the technique is to attach agents to each vehicle and
group of vehicles. The vehicle agents are programmed so they
achieve certain objectives, but in the event of some vehicles
being unable to fulfil their initially assigned tasks, others may
have their tasks assigned to them in order that overall goals may
still be attained, if possible. In business management terms,
this might mean workers and managers being automatically assigned
new tasks and responsibilities in the event of others falling
sick or leaving. Lyndon Lee, from BT described a proposal to
assign agents to enquiries made to call centres, to negotiate
with agents assigned to personnel and departments to direct
enquiries to the personnel best able to deal with them. In the
event of customers deciding to purchase services, agents would
route the order by a dynamically optimised path through the whole
process of checking credit, and finding resource to deliver.
Lee envisaged that if the enquiry or order is web based, the
computer system graphically show the user exactly how it was
being processed and where it had got to at any one time, in a
manner not dissimilar to Professor Marik's simulation of a self
optimising conveyor system. Other commercial companies known to
be seriously investigating the implementation of agent technology
include Daimler Chrysler and various Japanese car companies.
McFarlane expects to see partial system usage in industry in,
"The near future", with full agent usage in elements of
the supply chain in the next three years.
Centre for
Distributed Automation and Control
JADE
Professor Vladimir Marik
at Rockwell
Andrew
Ogden-Swift at Honeywell
Pointers
* Software agents can be attached to orders, products and the
resources used to manufacture them
* Agents act autonomously and negotiate with each other
* Agents can also advise other agents of events they should be
made aware of on a need to know basis
For more technical
developments see www.eurekamagazine.co.uk