The literature review in
precedent pages demonstrates that there is hardly any
mathematical formulation applied to the FMS design
problem, which uses a concurrent engineering modular
approach. The particular contribution of the modular
approach is to attribute responsibility for those decision
variables to four modules, which operate simultaneously.
The application of 3D model simulation principles to
a FMS case study shows that a common modelling language
can simplify inter-modular communication of strategic
design variable choices. The identification of globally
feasible solutions is relatively easy if detailed information
about the case study is provided in advance. The case
study information package presented in attachment includes:
In
the generic case, most of this information
will not be available before the FMS design expert
start
to propose and evaluate alternatives. The
total budget is likely to be estimated by
the team, new product design is likely to be
undergoing
changes
as the process design team progresses,
potential market demand is probably a task
for Production/Marketing
specialists, the definition of a production
technology is probably a task for FMS specialists
while
the
list of potential equipment is a task for
Automation and Robotics specialists.
The
expert, specialist in the FMS design, is
also optimising different
criteria
when assigning a set of weights to particular
strategic decision variables thus reflecting
a variety of
objective functions. These may include
the maximisation of flexibility,
reactivity in real time, equipment availability,
efficiency and the minimisation of production
costs and total
workload. The design below associates
these criteria to each of four modules identified
for the case
study. In each case, the optimisation
of
these criteria will
be subject to constraints such as product
design, production technology, budget, market
demand
etc. In the general
case, the number of modules and their
responsibilities will also be a design variable.
The
information about the total number and type of
machines, the need for sideways communication,
the organisation of production into cells and so
on may not be available in the early phases of
the FMS design process. In addition, the C&C
architecture that controls the entire production
system also links
the manufacturing plant to the corporate superstructure
(marketing, inventory control, finance, etc.).
This superstructure may not able to respond to
proposed
design features very early on. For these reasons,
the Command and Control module should be consulted
late in the design process, particularly if a concurrent
engineering design approach being used.
