NGHIEN Cflu TRAO DOl
(THQ D G N Q LY THaVET TflP Md CHflM OOfiH TINH TReNQ KY TH(16T CflC CUM, HE THOMQ TROMQ KHfil THfiC
TS. Nguyen Van Diing Hoc vien Ky thuat Quan sU
TOMTAT
Hien nay, ly thuyit tap md (Fuzzy logic) dd vd dang dudc Ung dung nhieu trong cdc linh vUc khoa hgc cong nghe. Tuy nhien, trong chdn doan ky thudt cdc phuong tien cd dgng viec Ung dung ly thuyit tap md vdn con Id vdn di mdi. Bdi bdo trinh bdy cdsdly thuyit tap md ang dung trong chan doan trgng thdi ky thuat cdc he thong phUc tap, tUdd, nghiencUu, Ung dung cong cu Fuzzy logK (phdn mim Matlab-Sim- ulink), dexdy diing chUdng trinh tinh todn xdc dinh hanh trinh dii trtt con lai cho he thingphanh xe du lich trong qud trinh sU dung.
TU khoa: Chan doan ky thudt, trgng thdi ky thudt, he thong phanh thuy liic, ly thuyit tap md, khai thdc xe.
ABSTRACT
Today, Fuzzy logic is widely used in many technologic fields. However, the Fuzzy logics applying il. vehicle diagnostics is new topic. The paper presents the basic of Fuzzy logic for diagnostic complex sptem; based on Fuzzy logic tool box (Matlab- Simulink), a program are designed to calculate the rest of using automotive hydraulic brake system.
Keywords: diagnostics, technical state, hydraulic brake system. Fuzzy logic, automobile mainte- nance.
a TAPCHlCOKHlVlfiTNAM • S6 4 (Thang4nilm 2012) Q S
NGHIEN CUfU-TRAO D 6 I
I.DATVANDE
Trong qua trinh khai thdc, trang thdi ky thuat eua cdc cu, eP cau, he thdng ludn thay ddi theo chieu hfldng xau di. De xdc dinh chinh xdc tinh trang ky thuat (TTKT)cho cae eum, h^ thdng dd, cd the sfl dung nhi^u phflpng phdp khdc nhau tren ca sd ly thuyet thdng tin ho^c ly thuyet dd (in c^y. Khi dd, can cd thdng tin rd rdng, day du vc h^
thdng. Tuy nhien, trong chan dodn ky thu^t khdng tdn tai ngfldng chinh xdc gifla trang thdi hdng vd khdng hdng, cdc dai ifldng do mang tinh ngau nhien, ddng thdi khdng the dinh nghia chinh xdc quan he gifla eac dai Iflpng eua cac thdng sd chdn dodn. Do dd, viec dp dung ly thuyet tap md xdc dinh TTKT Id hpp ly hon cd, ddc biet, vdi cdc h?
thdng phflc tap.
2. GIAI QUYET VAN DE 2.1. CPsdIy thuyet 2.1.1. Tapmd
Tap md A dflpc dac trflng bdi cac phan tfl dfla vao d dang mflc phu thudc /j^ gpi la ham lien thudc va dflpc ky hieu nhfl la bac phu thudc. Mflc phu thudc la gid tri bieu thi sfl ddnh gid khach quan cua con ngfldi ddi vdi trang thdi cua sfl vat.
Xet tap E bat ky, trong do cd tap con A.
Ham //^ cd the cd eac gia tri trong doan tfl 0 den 1. Tap con A la tap md (ky hieu Id A) va dflpc dinh nghia nhfl tap cua hai vee tP: A=(x, (x)), xeE
Vec tP X la dinh nghia eua phan tfl trong tap md A, vec to la ham lien thudc cua A. Khi dd, tap md dflpc phat bieu nhfl sau: Sd thflc eua ham (x) ddi vdi mdi phan tfl XEE dflpc coi nhfl la bac cua yeu to phu thudc eua A.
hi?n thong qua cdc gia tri: Do cao, mien xdc dinh vd mi^n tin c^y.
- Dp cao cua tap md A cdn gpi la dp phu thudc cua hdm phy thupc va ky hieu nhfl sau:
hgt(A) = sup //^ (x); xeE. Tap md phdi cd it nhat mdi phdn tfl ed dd cao bdng 1 va nd dflpc gpi la lap md chinh tdc, ngflpc lai gpi la tap md khong chinh tdc.
- Mien xdc dinh la tap hpp cdc phan tfl x cua tap md A cd //^ (x) >0;
- Mien tin cay la tap hpp cdc phan tfl x cua tap md Acd //^ (x) =1;
b. Cac dang ham phu thupc
Cac ham phu thudc cd the la cac ham vdi cdc dang dfldng cong tuy y gan vdi cdc hdm dai so ca bdn. Tuy vay, cae ham phu thudc dung trong ehdn dodn trang thdi vd dieu khien md thfldng chpn la cac ham tuyen tinh (Hinhl).
a fi r X a p Y S X
Hinh 1: Cac dang ham phu thupc 2.1.3. Cdc phep tinh logic vdi tap md 2.1.2. Hdm phu thugc
a. Cac dac tinh cua ham phu thuoc
*Logic md: Logic md la logic nhieu gid tri trong khoang tfl 0 den 1. Ddi hdi trong logic md la phai cd quy luat trong khoang nhd. Khai niem logic md ddng nghia vdi khai niem tap md. Bien logic Cdc dac tinh cua ham phu thudc dflpc the trong tap md la cac ham phu thudc.
TAP CHi CO KHi VIET NAM • Sd 4 (Thang 4 nam 2012)
NGHIEN CUfU TRAO D 6 |
*Cac phep tinh logic
- Phep so sdnh: Tap A la tap eon cua B nghia la A nam trong B neu: //^ (x) < /Ug (x). Tap A bang tap B neu ju^ (x) = jUg (x)
- Phip hdp: Neu C la tap dflpc tao thanh tfl phep hop cua hai tap A vk B thi nd dflpc ky hieu nhfl sau:
C = 3 U B - { ( A - . / / , ^ , ( . V ) ) , V : C G £ } ;
dday MAr^eix) = mm[^,(x) //^(A-)].
•Pbepgiao: Neu C la tap dflpc tao thdnh tfl phep
giao cua hai tap .4 va A thi nd dflpc ky hieu nhfl a. Menh de hpp thanh
trflc tiep bang ngdn ngfl, cac gid tri ngon ngfl theo dang quy luat "Neu- Thi". Bien md tdng quat cd dac trflng la moi thanh phan xeE la gia tri cua no theo ham phu thudc tflpng flng.
2.1.4. Suy luan md
Suy luan md sfl dung to hpp cac luat suy luan tren ca sd logic md (Cdc luat ghi cac ham quan he gifla bien md vao vd ra, trong chan dodn Id thdng so chan doan vd thong sd trang thai). Cac gid tri chan dodn vao la cdc tin hieu so, cdc so lieu cua ngfldi sfl dung, sd li^u cua he thong chuyen gia. Cac thong sd dau ra cua chan dodn tap md bao gdm trflc tiep cdc ham tflpng flng phu hpp vdi thdng tin ve tinh trang ky thuat cua ddi tflpng.
dday /i^_,(.v) = min[//,(j:) MSM]
- Phep bit: Neu tap C la tap hop bu cua tap A xac dinh trong E thi no ductc ky hieu nhu sau:
C = complA = {(:C,/^„„,PM{JC)), VJC e E}
*Quan he md
Moi tap hop nho R cua phep nhan khong ciing CO so 5 va 5 ta gpi la quan he cua tap A , doi vdi tap B . Quan he md khong cung cfl sd la quan he ma 6 do khong the xac dinh don dieu theo mpt CO s6, gifla chung ton tai quan he giiJa hai hay nhieu tap hpp khong ciing cO sd. Ddi vdi quan he md khdng cung co sd cd the dimg each ghi ma tran thdng thudng. Cac ham phii thupc q u a n h e / Z j f e ; ' ) ;
R = l{x.y) f,,(x,y))
Khi dd, ma tran chan doan cd the dung
Vdi quan he dpn dieu hay quan he nhieu thanh phan deu dupc thuc hien bang co cau suy luan "Neu - Thi". Suy luan md don dieu "Neu - Thi" trong dang ngon ngii cd the viet nhu sau:
Neu (X la TV) thi (Y la Y2). Hay: IF (Bieu thilc md) THEN (bieu thlJc md); Trong dd X va Y la cac bien md. TV va Y2 la cac gia tri ngon ngfl dupc dinh nghia trUc tiep cia tap md N,U trong khoang T va R.
Menh de nay cho phep til mpt gia tri dau vap xac dinh dupc lien flng thoi man yeu cau ket luan suy luan cua gia tri dSu ra va dupc gpi la menh de hop thanh vdi mdt dieu kien.
b. Miic phu thuoc cua ket qua suy luan Mflc phu thudc cia ket qua suy luan cua luat trong tap md cd gia tri trong khoang (0,1) va cd the ap dung cac phep tinh flng dung md tren co sd cac mflc phu thupc chp trfldc cua tien menh de.
LuSt IF - THEN CP the bieu thi nhd cac phep tinh flng dung. Neu MA (P)i MB (P) '^ cac gia tri cu the cua ham phii thudc MA Wi fa (y) can tim ham (x,y) la mflc phu thupc cua ket qua
TAP C H l CO KHi VIET NAM S6 4 (Thang 4 nam 2012)
NGHIEN CJU - TRAO 0(!)l
suy luan eua luat thdng qua cac phep tinh flng dung:
I (//^, (x), //g (y)) = fi^ (x,y) vdi quan he R;
iP^MAiP) (9./^«(9) Cdc phep toan flng dyng gdm t - Mamdan:
(y)) = min(//^(x), //„ (y)) - Larsen ;
l ( / ; , ( x ) , / / , ( y ) ) = ( / / , ( x ) . / / , (y)) - Lukasiewicz :
i ( A , ( x ) , ;/„(y)) = m i n d , I - / / | ( x ) + //fl(y)) - Zadeh:
I ( / / . ( x ) , MAY)))
/j^ (y)) = max(l- /y,(x),min(^^(x).
- Kleene - Dienes :
I ( / ^ , ( x ) , / / ^ ( y ) ) = m a x ( l - //^ (x), MBW)- c. Luat hpp thanh dieu kien
Tien menh de va lien flng cd nhieu thanh phan nhfl cdc gid thiet trong logic md ed the la nhan (ANDF), tdng (ORF) cua cdc phep tinh.
l a p tflpng flng vdi cdc quy luat Neu -Thi cua mdt sd gia tri (x,, x^, y), cac gid trj xac dinh mdt tap mdi trong khoang N^, N^, U dflpc bieu thi nhfl la tich cua ham md Tj.T^, R. Suy luan md Neu - Thi trong dang ngdn ngfl cd the viet nhfl sau:
Trong trfldng hpp cdc gia tri dinh trong khodng chuan ehflng ta da sap xep bdc phu thudc vdo mpt hay nhieu tap md tflpng flng vdi khdi iii?m ddc lap trong cdc luat, trong dd, chung ta chum kin khong thfla khodng true cua tap md tflpng flng, chung ta ndi Id da md hoa. Nhd qua trinh md hoa trong thflc te lap bang ham tflong flng hay bd sung cac bieu thflc phdn tich cua cdc hdm nay vd ti^p Id xdy dflng ham phu thupc cho cac phdn cua ti^n m^nh de. Neu nhfl tien m?nh de cfla eac luat cho trfldc ed nhieu hpn mdt phan, tflc id chung ta md hoa nhi^u bac phu thudc, chung ta se cd trflc titfp cdc phep md gia trj ddng nhat dai di?n cho ti^n menh de ddi vdi flng dung md.
Sdp xep dinh cua cdc gid tri ddi vdi tap md ra bdng gidi md. Trong chan doan chung ta hi^u giai md nhfl Id sdp xep cdc ham phu thupc vdi trang thai ddc lap trong dai Iflpng chan doan vao. Tren eP sd he thdng luat IF - THEN cua tap md ra ed dflpe, cd the ddnh gid trang thai cdc gia tri tflpng flng cua mflc phu thudc vd khdng tien hdnh giai md. Giai md la phep tinh eP ban cua dieu chinh md.
Khi da cd dflpc do thi bieu dien tdp md ta cd the tien hdnh giai md bdng cdc phflpng phdp khdc nhau nhfl sau:
- Phflpng phap trpng tam dien tieh (COA) bao gdm tinh toan tat ea cdc gia tri gom cua dien tich bieu dien tap md va xac dinh toa dd trpng tam eua ehflng, dd la cac gia trj trung binh nam tren true ngang cua bien ra ngdn ngfl.
- Phflpng phap trpng tam eua eac phan (COS). Tflc la di xdc dinh toa dp trung binh cua trpng tam dien tich cung mflc tren cdc true toa dp cua do thi.
Neu (X| la Al va ... va x^ la A'^ Thi (y la Y^) Neu he thong cd m dau vdo vd n dau ra thi cd the tach thanh n he nhd, mdi he nhd cd m dau vdo tfl Xj den X_^ va mdt dau ra la Y.
d. Md hod va giai md
- Phflpng phap ldn thfl nhat FOM - Phflpng phap ldn sau cung LOM - Phflpng phap tam dien tieh BOA - Phflpng phdp tam dien tich ldn nhdt MOM 2.2. Lfng dung Fuzzy logic xac dinh trang thai ky thuat h^ thdng lai trin xe Matiz
TAP CHi CO KHi VIET NAM V Sd 4 (Thang 4 nam 2012)
NGHIEN CljfU-TRAODOl
He thdng lai tren xe Matiz la he thdng lai dan ddng CP khi, trp lflc thuy lflc. Cd the sfl dung cdng cia Fuzzy logic trong phan mem Matlab de xdy dflng chflpng trinh chan dodn xac dinh trang thdi ky thuat cho he thdng trong qua trinh khai thac.
2.2.1. Xdc dinh cdc bien vdo - ra
Qua phdn tieh he thdng, chung ta chpn dflpc 07 bien vdo va mdt bien ra. Bien vao la cae thdng sd chan doan dac trflng nhat eua he thdng.
Bien ra la tinh trang ky thudt cua he thdng can xdc dinh. Cac bien vao va bien ra cua he thdng dflpc the hien d Bang 1.
Bang 1: Cac bien vao - bien ra cua he thong
Bang 2: Cac gia tri ngon ngfl cua bien vao
S I I
1
;
3
4
6
'
Bien vao (thir Dguyen)
Do rc'^ I l l l lai' do 1 Lir; loii iihit tren \ jiili iji i \ i Do x:l.lvjOT!2 diij\fii ito!i2 ouao;oireiicijo:i£i:iii Do ie:l. goc cfiu\ ni IJUCHS aiua hai banh xe dan huong ' d o .
Ap sua' oua dau tro luo P1 tronahf thon^ikG cin-i Ap suat cua dau iro lite PI trong he thong (IcO cm-j Ap suat ciia dau tn? lire P3 tron" he th6n_g (kG cm-)
Ky hieu R L LH
LG
PI
p;
Vi Bieu ra
(Ihir Il2U^ell)
Tinh trang k\' thuat cua he thoug
!ai tro hrc thu)." b e t r e n x e o t O ' % 1
K} hieu
1
TTKT ST I
1
-
J
4
:
6
B i e n vao
D o i c vanh lai i d o ;
Lu-c 1cm nhat tren vanh lai ;^"") Do lechhu"3ng c h m ' a i d o n g cua 6 t
tren du^^na (m) Chenh lech goc chu\'en hudng giO-a
hai banh xe dan hccjn? iio) Ap iuat cua dau tra
lu"c PI trong he thons [kG cm-) Ap iuat cua d i u trcr luc P2 trong he thonj
(kG cm-) Ap 5uat cua dau t i a
lire P3 trong he thong (kG c n r )
Gia tri n g o n ngu' Dci I a nho D o 1 cr ••.•ua Do i c l o n Luc nho Luc '.'ua Luc Ion Sblechnlid Dtilechvxa D o lech Ion
Cherfikdiiiio Qerhledi^-ua Cleriiledibn Ap i u i t nho Ap ; u i t vua Ap iuat 1cm Ap iuat nho Ap suit VU3 Ap iuat Icrn Ap i u i t nho Ap suit \\ja Ap iuat Ion
K y hieu
RB R \ ' RL LB L \ ' LL LHB L H \ ' LHL LGB LG\"
LGL P I B P l \ ' P I L P:B
?2\' P:L P3B P 3 \ ' P3L
Cac gia tri ngdn ngfl eua bien vao la cae tap md con, nd chinh Id nhflng khoang cua bien vdo ma the hien bang ngdn ngfl, song nd lai bao trum Ien tat ea nhflng kha nang cd the cua bien vao. O day, mdi gia tri bien vdo cd ba gid tri ngdn ngfl (bdng 2).
b. Gia tri ngdn ngfl cua bien ra
2.2.2. Xdc dinh gid tri ngon ngU cua bien vdo vd Vdi he thdng chan dodn la he thdng Idi trp bien ra lflc thuy lflc ta chpn mpt bien ra duy nhat. Gia tri ngdn ngfl cua bien ra la 5, tflpng flng vdi nd la a. Gia tri ngdn ngiif cua bien vao nam tap rod con (bang 3).
TAP CHi CO KHi VIET NAM V So 4 (Thang 4 nam 2012)
NGHIEN cflu - TRAO DOI
Bang 3: Cdc gid tri ngon ngfl cua bien ra STT
1
Bien ra Tinh trang ky thuat cua he thong lai tra luc thu\- lu-c
Gia tri ngon LaniMec tot Lani ^'lec binh thuan?
LaniMec keni Hon? nhe Hong nang
Ky hieu TOT BT KE HNh
KS
Tren cd sd cdc gid tri trin, tien hdnh phdn khodng md cho cdc bi^n di' lam cd sd xdy dUng cdc Itial chohimd.
2.2.4. Xdy dUng ludt cho he md
Dfla vdo bdn chdt vat ly, sd lieu do dac va kinh nghiem eua chuyen gia trong qud trinh khai thac sfl dting xe ndi ehung vd h? thdng dan ddng di6u khi^'n thuy lflc ndi rieng di xay dflng cdc luat cho h^ md tr^n cP sd luat I F - THEN (Neu- Thi).
2.2.3. Xdc dinh gid tri hdm thugccho tiinggid tri ngon ngd
Cdc thdng sd vdi hdm phii thupc dflpc chpn theo dang hinh thang vdi cac diem dac trflng la . Cdc diem dae trflng tflpng flng vdi 4 dinh eua hinh thang, Khi chpn cdc diem cho cdc thdng sd can dfla vao gia tri ngfldng cua tflng thdng sd, dam bdo phu het gid tri ede thdng sd vd ehfla dflng nhflng hdng hdc cd the xay ra trong qua trinh sfl dung. Cac thdng sd cua hdm thudc dflpc chpn vd bieu dien trong bang 4.
Bang 4: Cac gia tri ham phu thupc Bien^ao ra
36 r J lanh lii
Lvc Ion nhat iren \ anh lai 3t) lech hi;ai|
chiR en dong cua oto tien ivunz, (m) So lech goc chiT.'m huong gii>a hai banh xe danh;:mg
' 3 (J;
.•^ iuat PI (kGcm-) .Apiuat P :
(kG cm-) A^ iualB {kGcm-)
Gia tri ngon ngtt 36 13 nho D6r3^i;a 1>Q 13 l311 Luc baihnho Luc • ua Luc 1cm Do lech nho 3o lech ^'ua 3o lech Ion Chenh ledi nho Chenh lech
^ua Chenh ledi Ion .Ap suat nho .•\p suat ^ ua .•\p suat lan .Kp :uat nho Ap sml -. i;a .Ap iuat Ion .Ap :uat nho Ap suit •. ra Ap suit Itm
Kl
RB R\"
RL LB
\.\
LL LHB LH\"LHL LGB LG\' LGL FIB PIV PIL P:B P:\"
P:L PJB P3\"
F3L
Cac thong so ham phu thuoc
iX 3
11
'
13 r 0 1
:
01 04 0 ? 50 54 60 i:o i : : i ; ; 116 lis i:i
^
3 6 3 t l i ; 19 0 1,5 2,S 0,1 06 1 1 50 54 6:I:D 123 i;6 116 119 i : :
j
"
10 13 r : i 1
;
30,4 09 1"=
34 60 66 V 12;
i:s l i s r i VA
0
6 S 10 V 19 : i 1 >
3 0,6 1 i 1 : :6 6:
66 123 126 I2S 119 122 124
Sau khi da xdy dflng xong khdng gian md cho cac bien vdo vd ra, tfl man hinh Membership Function Editor vdo Edit chpn Rules Editor ta thay mdn hinh Rules Editor xuat hien.
Tai mdn hinh nay ta xdy dflng luat cho he thdng dfla vdo kinh nghiem cua chuyen gia.
O ddy ta xay dflng c, e luat, sau mdi luat chpn Add rule vdi trong so (Weight) cua he chpn l a i .
Viec xay dflng luat dieu khien la khau rat quan trpng quyet dmh den do chinh xac cua bai toan. Ta phdi chpn nhflng luat thfldng xdy ra nhat trong qud trinh sfl dung, so Iflpng luat cang ldn, dp chinh xdc cang cao.
2.2.5. Hien thi ket qud chdn dodn
Tfl mdn hinh Rule Editor ta vao View chpn Rule cho ta ket qud ve trang thai ky thuat tflpng flng vdi cdc gia tri cua cac thdng so chan dodn (Hinh 2). Qua hinh 2 ta thay, tflpng flng vdi dp ro vanh lai: R = 6,5 (dp), lflc tren vanh tay lai:
L= 16 (N), dp lech hfldng: LH =1,5 (m), lech gdc:
LG= 0,8(dp), dp suat
? = 58(kG/cm^), dp suat V = 124(kG/cm^), dp suat P3= 120(kG/cm^), hanh trinh dfl trfl cdn lai eua he thdng la 55%.
TAP C H i CO KHi V I £ T NAM Sd 4 (Thang 4 nam 2012)
NGHIEN CljfU - TRAO OOl
H t-i'li- \/"-.vi-':l)()l>IIIIOr>K.
Opened ivi(emE'Or>IUONG l^rule^
I " - I
Hinh 2: Man hinh hien thi ket qua
3. KET LUAN
Bai bao da trinh bay flng dung ly thuyet tap md, tren ca sd sfl diing cdng cu Fuzzy Toolbox trong phan mem Madab-Simulink de chan doan xac dinh trang thai ky thuat he thdng lai ed trp lfle thuy lflc tren cac phflpng tien ca gidi. Ket qua nay ed the dung lam ca sd de nghien cflu chan dodn ky thudt cac he thdng khac tren xe d td. •
Tai lieu tham khao:
[I]. Nguyen Van Kieu. Thuy khi ddng lflc ky thuat. Hpc vien Ky thuat Quan sfl, 1999.
[2]. Phan Xuan Minh. Ly thuyet dieu khien md. NXB. Khoa hpc & Ky thuat, 2000.
[3]. Nguyen Khac TraL Ky thuat chan doan 6 to. NXB. Giao thdng Van tai, 2007.
[4]. Martin t. Stockel.Auto Service and repair. Suoth Holand Ihnois, 1992.
[5]. Prof. ing. Marcel. Kredl. Csc. Diagnosticke systemy. Vydavatelstvi CVUT, 1997.
[6], Uwe Heisel. Simulation with Matlab- Simulink. Stuttgart Verlag, 2006.
TAP CHi C O KHi V I | T NAM • S6 4 (Thang 4 nam 2012)
