Expert System of Sewing Machine
Based on UML
The system function is the selection of small and
medium electric motors. When the users input the certain
known motor parameters, one or more motor models
selected in the system will be showed. This kind of
problem that has data-driven feature is suitable for the
rule based language with forward inference. The typical
case is reading in one group of motor parameter the each
program cycle and deducting until obtaining all the
possible conclusions according to input data. As shown
in Figure 1 is the flowchart of the expert system.
Fig. 1 Flow chart of Motor Selection
The unification of data is a very important step in this
system. That means at the stage of setting up the
knowledgebase, some motor parameters have been
systematically standardized and can be recognized by the
system. Taking the speed control for example, each user
may have their specific requirements of speed. To be
exhaustive, some fuzzy selection functions will be lost
and the user’s choice will be limited. Therefore this paper
will categorize the speed range to high, low and none
((speed range high), (speed range low), (speed range
4-1069
The Ninth International Conference on Electronic Measurement & Instruments ICEMI’2009
zero)).This not only facilitates the establishment of the
system, but also makes the selection of speed easier.
When the users choose the speed, they don’t need to
consider the actual data and all they need to know is the
scope of the speed range. After the data standardization
is finished, the rule is needed to control the data. The
rule verifies the match degree of the input data and the
knowledgebase by pattern matching [3] [4].
During the actual operation of the expert system for
motor selection, some kinds of functions must be
showed, such as outputting the following motor
parameters according to the input data: the motor model,
the protection and structure form, the rated power and
cooling ventilation, the rated speed. Of course, these
contents can be outputted individually or in combination.
And finally the users determine the required motor
according to these dates. System functions as follows:
1) Motor selection function: The users input the data
according to various motor parameters into the system.
The system chooses the relative rules based on the data
from the rule base. Then it uses the rules to reason the
results. At last the results of the rule inference are given
and displayed to the users.
2) Add, Modify and Delete the rules: The user can
add some rules through the system. In practical use, the
users may find that there are some discrepancies between
the rules and the actual situations. So adding, modifying,
or deleting the rules according to the actual situations
can expand the system and provide better service for the
users.VS enterprises
3) Add, Modify and Delete the facts: Likewise, the
operation of fact base is also essential. In practical use,
there are all kinds of problems. However the fact of this
system is only the result in general case. So adding,
modifying, deleting the facts is also a necessary means
to make the system more and more clever.
B. The establishment of fact base
The establishment of fact base of motor selection,
mainly list out the various parameters of the motor,
different properties and the types of motor and is used to
activate phase matching rules to carry out the selection
of the motor.
1) The fact base of determining the types of motor
according to the load property, the request of production
process on the start, brake, turnover speed control, such
as:
Fact 1 (Speed range Large)
Fact 2 (Speed range Free)
Fact 3 (Speed range Small)
Fact 4 (Speed smoothness none)
2) The fact base of determining the types of motor
according to the situation of the network voltage, voltage
grade, such as:
(Rated voltage 440v)
(Rated voltage 220v)
(Rated voltage 160v)
(Motor type: Three-phase Asynchronous Motor)
(Motor type: Single-phase Asynchronous Motor)
(Motor type: DC Motor)
3) The fact base of determining the protective form
and the method of cooling ventilation according to the
environmental conditions, such as:
(Solid type: Solid diameter> 50 mm)
(Solid type: Solid diameter> 12 mm)
(Solid type: Solid diameter> 1 mm)
(Solid type: Dust)
(Waterproof type: Anti-drip)
C. The establishment of rule base
1) The definition of rule base
On the basis of the definition of fact base and the
knowledge of motor selection, the parameters which are
needed to identify when selecting motor, can summarize
as follows: motor type, protective form and structure
form, rated power and cooling ventilation method, rated
speed. As shown below:
Rule using the form if then or
Basis of the knowledgebase which based on the fact
above, the effect of the rule is utilizing the knowledge in
the knowledgebase and justifying by the expert
knowledge. Therefore, it is necessary to know the
contents of the knowledgebase before setting up the
expert system and set up the rule base of controlling
knowledge combined with expert knowledge and
experience.
2) The expression for rule base
By summarizing and concluding all knowledge
points above, the rule base of the electromotor choice
expert system can be described as follow:
(1) Motor type
if Speed range = Large then motor type = DC Motor
if Speed range = None then motor type = Cage
Asynchronous Motor
if Starting torque = large then type = DC Series Motor
if Speed range = None and motor capacity = Large
then motor type = Synchronous Motor
if Speed range = Small and speed smoothness = None
then motor type = Variable Class and Variable Speed
Motor …
(2) The protection type of motor
if Solid type = Solid diameter> 50 mm and Waterproof
type = Anti-drip then Protection level = IP11
if Solid type = Solid diameter > 12 mm and
Waterproof type = Anti-drip then Protection level =
IP21
if Solid type = Solid diameter > 12 mm and Waterproof
type =15 ‘ Anti-drip then Protection level = IP22 …
(3) The selection of cooling ventilation
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