ST52T441 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST52T441

8-BIT INTELLIGENT CONTROLLER UNIT (ICU) Timer/PWM, Analog Comparator, Triac/PWM Timer, WDG

STMicroelectronics 

ST52T400/T440/E440/T441

2.3.3 Inference Phase.

The Inference Phase manages the alpha weights

obtained during the fuzzyfication phase to com-

pute the truth value (Ω) for each rule.

This is a calculation of the maximum (for the OR

operator) and/or minimum (for the AND operator)

performed on alpha values according to the logical

connectives of fuzzy rules.

Several conditions may be linked together by lin-

guistic connectives AND/OR, NOT operator and

brackets.

The truth value ω and the related output singleton-

move to the Defuzzyfication phase in order to

complete the inference calculation.

Figure 2.9 Output Membership Functions

j-th Singleton

1

ω

ij

ω

i0

ω

in

0

X

X

i0

ij

X

i-th OUTPUT

in

Figure 2.8 Fuzzyfication

IF INPUT 1 IS X1 OR INPUT 2 IS X2 THEN .......

α1

α2

X1

Input 1

X2

Input 2

OR = Max

IF INPUT 1 IS X1 AND INPUT 2 IS X2 THEN ......

α1

α2

X1

Input 1

X2

Input 2

2.3.4 Defuzzyfication.

In this phase the output crisp values are deter-

mined by implementing the consequent part of the

rules.

Each consequent Singleton Xi is multiplied by its

weight values ωi, calculated by the Fuzzy Infer-

ence Unit, in order to compute the upper part of

the defuzzification.

Each output value is deduced from the conse-

quent crisp values (Xi) by carrying out the follow-

ing defuzzification formula:

where:

N

∑ Xijωij

Yi

=

----j-----------------

N

∑ ωij

j

i = 0,1 identifies the current output variable

N = number of the active rules on the current out-

put

ωij =weight of the j-th singleton

Xij = abscissa of the j-th singleton

Fuzzy outputs are stored in the RAM location i-th

specified in the assembler instruction OUT i.

26/94

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