GSR Fuzzylogic

7/23/2019 GSR Fuzzylogic

http://slidepdf.com/reader/full/gsr-fuzzylogic 1/19

Artifcial Intelligence - Fuzzy Logic

-Gopal Singh Rawat



What is Fuzzy Logic?

• Fuzzy Logic (FL) is a etho! o" reasoning thatrese#les huan reasoning$ %he approach o" FLiitates the way o" !ecision a&ing in huans thatin'ol'es all intere!iate possi#ilities #etween !igital'alues S an! *+$

• %he con'entional logic #loc& that a coputer canun!erstan! ta&es precise input an! pro!uces a !efniteoutput as %R, or FALS which is e.ui'alent tohuan/s S or *+$

• Fuzzy Logic Systes (FLS) pro!uce accepta#le #ut!efnite output in response to incoplete a#iguous!istorte! or inaccurate ("uzzy) input$



• %he in'entor o" "uzzy logic Lotf A. Zadeho#ser'e! that unli&e coputers the huan

!ecision a&ing inclu!es a range o" possi#ilities#etween S an! *+ such as 0

• 2R%AI*L S

• 3+SSI4L S• 2A**+% SA

• 3+SSI4L *+

• 2R%AI*L *+

• %he "uzzy logic wor&s on the le'els o" possi#ilitieso" input to achie'e the !efnite output$



Ipleentation

• It can #e ipleente! in systeswith 'arious sizes an! capa#ilitiesranging "ro sall icro-controllersto large networ&e! wor&station-#ase! control systes$

• It can #e ipleente! in har!wareso"tware or a co#ination o" #oth



Why Fuzzy Logic?

• Fuzzy logic is use"ul "or coercialan! practical purposes$

• It can control achines an!consuer pro!ucts$

• It ay not gi'e accurate reasoning#ut accepta#le reasoning$

• Fuzzy logic helps to !eal with theuncertainty in engineering$



Fuzzy Logic Systems Architecture

•

It has "our ain parts as shown



• Fuzzifcation Module 0 It trans"ors thesyste inputs which are crisp nu#ers into

"uzzy sets$ It splits the input signal into f'esteps such as 0

• Knowledge Base 0 It stores IF-%5* rulespro'i!e! #y e6perts$

L3 6 is Large 3ositi'e

73 6 is 7e!iu 3ositi'e

S 6 is Sall

7* 6 is 7e!iu *egati'e

L* 6 is Large *egati'e



• Inerence !ngine 0 It siulates thehuan reasoning process #y a&ing "uzzy

in"erence on the inputs an! IF-%5* rules$

• "euzzifcation Module 0 It

trans"ors the "uzzy set o#taine! #y thein"erence engine into a crisp 'alue$



Mem#ershi$ Function

• %he e#ership "unctions wor& on "uzzy sets o"'aria#les$

• 7e#ership "unctions allow you to .uanti"y linguistic

ter an! represent a "uzzy set graphically$ Ae#ership "unction "or a "uzzy set A on theuni'erse o" !iscourse 8 is !efne! as 9A:8 ; <=>$

•5ere each eleent o" 8 is appe! to a 'alue#etween = an! >$ It is calle! e#ership 'alue or!egree o" e#ership$ It .uantifes the !egree o"e#ership o" the eleent in 8 to the "uzzy set A$



• 6 a6is represents the uni'erse o" !iscourse$

• y a6is represents the !egrees o" e#ership in the <= >inter'al$

• %here can #e ultiple e#ership "unctions applica#le to"uzzi"y a nuerical 'alue$ Siple e#ership "unctions areuse! as use o" cople6 "unctions !oes not a!! oreprecision in the output$

•

All e#ership "unctions "or L3 73 S 7* an! L* areshown as #elow 0



• %he triangular e#ership "unction shapes are ostcoon aong 'arious other e#ership "unction shapessuch as trapezoi!al singleton an! Gaussian$

•

5ere the input to @-le'el "uzzifer 'aries "ro ->= 'olts to>= 'olts$ 5ence the correspon!ing output also changes$

!%am$le o a Fuzzy Logic System

• Let us consi!er an air con!itioning syste with @-le'el "uzzylogic syste$ %his syste a!Busts the teperature o" aircon!itioner #y coparing the roo teperature an! thetarget teperature 'alue$



Algorithm• Cefne linguistic'aria#les an! ters$

• 2onstruct e#ership

"unctions "or the$• 2onstruct &nowle!ge#ase o" rules$

• 2on'ert crisp !ata into"uzzy !ata sets using

e#ership "unctions$("uzzifcation)

• 'aluate rules in therule #ase$ (in"erenceengine)

•

2o#ine results "roeach rule$ (in"erenceengine)

• 2on'ert output !ata intonon-"uzzy 'alues$

(!e"uzzifcation)



Logic Ce'elopent

Ste$ &' "efne linguistic (aria#les and terms

• Linguistic 'aria#les are input an! output 'aria#les in the "oro" siple wor!s or sentences$ For roo teperature col!war hot etc$ are linguistic ters$

%eperature (t) D E'ery-col! col! war 'ery-war hot

• 'ery e#er o" this set is a linguistic ter an! it can co'ersoe portion o" o'erall teperature 'alues$

Ste$ )' *onstruct mem#ershi$ unctions orthem

• %he e#ership "unctions o" teperature 'aria#le are as

shown 0



Ste$+' *onstruct ,nowledge #ase rules

•

2reate a atri6 o" roo teperature 'alues 'ersus targetteperature 'alues that an air con!itioning syste ise6pecte! to pro'i!e$



oomem$ /arget

0ery1*old

*old 2arm 3ot 0ery13ot

eryH2ol! *oH2hange 5eat 5eat 5eat 5eat

2ol! 2ool *oH2hange

5eat 5eat 5eat

War 2ool 2ool *oH2hange

5eat 5eat

5ot 2ool 2ool 2ool *oH2hange

5eat

eryH5ot 2ool 2ool 2ool 2ool *oH2hange

• 4uil! a set o" rules into the &nowle!ge #ase in the "or o" IF- %5*-LS structures$

Sr .4o.

*ondition Action

> IF teperatureD(2ol! +R eryH2ol!) A*CtargetDWar %5*

5eat

IF teperatureD(5ot +R eryH5ot) A*CtargetDWar %5*

2ool

J IF (teperatureDWar) A*C (targetDWar) %5* *oH2hange



Ste$ 5' 6#tain uzzy (alue

• Fuzzy set operations per"or e'aluation o" rules$ %heoperations use! "or +R an! A*C are 7a6 an! 7in

respecti'ely$ 2o#ine all results o" e'aluation to "or afnal result$ %his result is a "uzzy 'alue$

Ste$ 7' 8erorm deuzzifcation• Ce"uzzifcation is then per"ore! accor!ing to e#ership

"unction "or output 'aria#le$



A$$lication Areas o Fuzzy Logic

• Automoti(e Systems Autoatic Gear#o6es

Four-Wheel Steering

ehicle en'ironent control

• *onsumer !lectronic9oods

5i-Fi Systes 3hotocopiers

Still an! i!eo 2aeras

%ele'ision

• "omestic 9oods 7icrowa'e +'ens

Re"rigerators %oasters

acuu 2leaners

Washing 7achines

• !n(ironment *ontrol Air

2on!itionersKCryersK5eaters

5ui!ifers

%he &ey application areas o" "uzzy logic are as gi'en 0

Ad t "i d t



Ad(antages oFLSs

• 7atheatical concepts

within "uzzy reasoning are'ery siple$

• ou can o!i"y a FLS #y Busta!!ing or !eleting rules !ueto e6i#ility o" "uzzy logic$

• Fuzzy logic Systes can ta&eiprecise !istorte! noisyinput in"oration$

• FLSs are easy to constructan! un!erstan!$

•

Fuzzy logic is a solution tocople6 pro#les in allfel!s o" li"e inclu!inge!icine as it rese#leshuan reasoning an!!ecision a&ing$

"isad(antages oFLSs

• %here is no systeaticapproach to "uzzysyste !esigning$

• %hey areun!erstan!a#le onlywhen siple$

• %hey are suita#le "or

the pro#les which !onot nee! highaccuracy$



4i#liography K Sources :

• http:KKwww$seattlero#otics$orgKenco!erKarMNK"uzKin!e6$htl

• wi&ipe!ia$org

•

tutorialspoint$co

http://www.seattlerobotics.org/encoder/mar98/fuz/flindex.html




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GSR Fuzzylogic