Abstract:
The manufacturing systems of the future will possibly be
radically different from the present day conventional ones:
NC, FMS, CIM, MAP etc. will be common terminologies in the
future plants. This development phenomenon will have its
consequential influence on the production systems of the
developing countries, which depend to a large extent on the
hardwares of the developed countries. At the same time the
manufacturing sectors of the developing countries are facing
a further threat from those of the developed, the NICs and
the petro-dollar countries; thus the developing countries
are losing th~ir knowledge containers (viz. shop supervisor,
production planners etc.), which need a long lead time for
generation. Expert Manufacturing System (EMS) is being'
proposed to help the developing countries (like Bangladesh)
out of this problem. The model of an EMS is being proposed
to take account of this structural change in hardware and
humanware technologies.
The EMS consists of mainly three parts 1.e. 1) Knowledge
Base, 2) Inference Engine and 3) User interface. The
knowledge base of an expert system contains both declarative
and procedural knowledge. The procedural knowledge is
represented by rules.
For declarative knowledge two data bases namely static data
bases and dynamic data bases are used. The inference engine
is the control and, inference strategy of the system. For
inference strategy modus ponens is used and for control
strategy branching method is used. The reasoning are
governed here by forward chaining. The user interface
component enables the user to communicate with an expert
system.
For the development of the system it is assumed that the job
is to be a plug type job with three external surfaces and
the sy.stem is capable of selecting blank, fixtures and
identifying required operations and their sequences. A
suitable one is selected among the available blanks on the
basis of minimum material removal. The operat ions
identification is done on the basis of logical sequence of
operations. The selection of fixtures is done on the basis
of minimum job deflection; here only some job holding and
extra supporting devices of a conventional machine tool such
as lathe is considered.
To develop EMS, PROLOG is used for programming and it runs
on an IBM PC with an MS DOS operating system.
To implement the EMS, no special computer knowledge is
necessary, only some physical job characteristic should be
inputed into the system through man-machine interaction.
The results obtained by EMS is more logical and the
interaction procedure is friendly.
