XAC DJNH CAU TRUC TOI UtJ CUA CHU KY SU^A CHU^A CUA THIET BI VAN TAI CO TINH DEN CHI PHI VA MlTC TIN CAY
CHO T R r 6 c
GVC. Vo trpng Cang^, GS. TS. Dd Ddc TuSn^
' Trudng Dgi hgc Bdch Khoa, BHQG - HCM, ^Trudng Bgi hgc Giao thdng Van tdi, Hd Ndi Tdm tdt: Bdi viit trinh bdy ca sd xdc dinh cdu true tdi uu eua chu ky sira chUa thiit bi van tdi tren ea sd gid thdnh sua chica vd mice tin cdy cho trudc, thi hiin bdng tudi thg gamma-phdn trdm cua chi tiit Tic gidi thudt ta thiit lap chuang trinh tinh todn edu true tdi uu cua chu ky sica chica cda thiit bi van tdi.
Tu khda: Tdi uu hod, Chu ky sica chUa, Thiit bi van tdi. Do tin cdy.
Abstract: The paper presents the basics for determination of the repair cycle optimized in consideration of repair costs and given level of reliability parameters through gamma-percent lifetime of parts. From this algorithm a program has been carried-out to optimize the repair cycle of the means of transport.
Keywords: Optimization, Repair cycle. Transport means. Reliability.
1. Gidi thif u chung
Cau tnic ciia chu trinh siia chQa phu thugc vao cac chi tigu kinh tg-ky thuat lam viec cua phuang tign ciing nhu cac chi phi cho khai thac va stra chiia. Cac chi phi cho siia chiia mgt bg phan rieng biet nao do dugc xac dinh bdi gia thanh phuc hii ciia no va bdi, bg phan do se dugc sua chiia thudng xuyen nhu thg n^o, nghTa la chiing phu thu6c vao khoang thdi gian Iam viec ciia b6 phJin giii'a cac thdi diera phuc hoi. Chi phi don vi tong cgng cho phuc h6i phuang tien (PT) dugc ting hgp tu' cac chi phi phuc hoi cac bg phan rieng biet:
Trong do: n- so lugng cac bg phan; C,-- gia thanh phyc hdi bg phdn thii i; I , - chu ky sua ch&a ciia bg phan thii i (km.)
Vi rdng ham ciia cac chi phi dan vj ting cdng cho phuc hdi cac bg phan dang xet la ham cua n bien so, cho nen co the viet:
M A
De t6i uu boa he thong bao duong ky thuat va siia chiia PT cdn tien hanh tii thieu hoa cac chi phi dan vi tong cgng cho viec bao dudng cd ki hoach, co xet tdi cac chi phi gay ra bdi cac sua cbiia ngoai kg hoach, va cac chi phi lien quan den viec dua PT ra khoi qua ttinh khai thac de tien hanh tdt ca cac dang kiem tra va sua chiia.
2. Gid thdnh phuc hii kha nang lam viec cua chi tiit vd bg phan
? ( i „ i j , . . . , i j = (2)
Su toi uu ciia mgt he thong siia chiia phu thugc dang ke vao gia thanh phuc hoi cac b6 phan rieng biet C, vi do la thudc do cua lao dgng song va lao dgng vat chat hoa, chi phi cho viec phuc hoi kha nang lam viec ciia no.
Gia thanh phuc hoi ciia bat ky bg phan nao cung bao gom cac khoan chi phi cho giai the cum may, vSt lieu va phu timg (con neu bg phan dugc thay mdi, thi se la gia thanh diy dii cua no); tien c6ng lao dfing de thirc hien cac cong vigc sua chua. Trong do cflng bao gim ca cac ton hao do thai gian dung cua PT de phuc hoi b6 phan can siia cbila.
Gia thanh phuc hoi moi bg phan phu thu6c dang ke vao cau tnic cua chu trinh sua chiia, no can dugc xac dinh true tiep trong qua trinh xay dung cau truc[l,3,6]. Ta xem xet mgt vi du sau day:
Gia sir co 3 bg phan vai cac so hieu /, J, k, sao cho I, <l <If, cac khoang thai gian phuc hoi cac bg phan nam trong moi quan he sau:
tj < T^ < T^. Neu cac bg phan j va k thugc cung mgt cum may va cau tnic cua chu trinh sua chiia dugc thuc hien nhu the hien tren hinh 1, thi cac ton hao do thai gian dimg ciia PT trong sua chiia doi voi moi bg phan trong so do se bj gioi han bai cac bg phan khac nhau. Chu trinh siia chiia bao gom 3 dang siia chira: a dang thii nhat tien hanh phuc hoi bg phan / ; a dang thii hai tien hanh phuc hoi bg phan / va J; d dang thii ba- phuc hoi tat ca 3 bg phan /, / va k. Trong gia thanh phuc hoi bg phan i a dang sua chiia thii
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Journal of transportation science and technology, Vol 15, May 2015
nhat bao gim ca cac ton bao do thai gian dimg PT trong thai gian phuc hoi bg phan nay.
Khi xac djnh gia thanh phuc hii cua bg phan thii j a dang sua chiia thit hai cac ton hao do dimg PT se khong can xet den, \d rang TJ < r,. va cac t6n hao da bao ham tiong gia thanh phuc hoi bg ph|n / . Tuy nhien cSn phai tinh din gia thanh ciia cac c6ng vigc lap rap-giai thi ciia cac bg phan i va j , vi rang chiing thugc cac cum may khacnhau[l].
^ ^
Hlnh 1. Mgt vi du cdu tnic chu trinh sua chUa Khi tinh toan gid thanh phuc hii bg phSn k a dang siia chiia thii 3, trong thanh phiin ciia no phai bao g6m cac ton hao do dimg PT trong khoang thoi gian 7^ — r , , vi cac ton hao do dimg PT trong khoang thoi gian r,- da dugc tinh vao (dua vao) gia thanh phuc bii cua bg phan i, con thai gian dimg ciia PT trong siia chiia dugc tinh bai thoi gian phuc hoi r^ ciia bg phan k. Tuy nhien, cac chi phi cho viec giai the va lap rap cym may kb6ng nam tiong gia thanh cua b6 phan k, vi chiing da dugc dua vao gia thanh cua bg phan J. Trong cac to hgp khac cua cac thao tac phuc hoi, CO nghia la a mgt cau tnic khac cua chu trinh siia chiia, trinh tu tinh toan cac gia thanh phuc hoi kha nang lam viec ciia cac bg phan cung c6 these khde di.
Nhu viy, cac chi phi cho vi8c phuc hii cac bg phan a cap siia chiia co khoi lugng da cho phu thugc vao khoang thai gian phyc hoi va su phu thugc vao viec moi bg phan thugc ve mgt cum may.
Cac chi phi day dii cho phuc hoi moi cum may:
Cj.,=C^, + C„, + C,„- (3) tiong do: Cjj^i- gia thanh truug binh phuc hii true tiip bg phan i, bao gim cac chi phi vat heu, tiin cong lao dgng, con neu bg phan dugc thay mai, thi do la gia thanh toan phan ciia no; C,^^ - cac tin hao trung binh do dimg trong thoi gian mgt Ian phuc hoi bg phan / ; C,„ - cac chi phi trung binh cho viec tat may, giai thi va l4p rdp cum may, ma b6 phan i nam tiong d6.
Khi phuc hii h& phan / , cac chi phi cho vat tu va lao dgng luon luon phai dua vao gia thanh
chung Cy., con cac tin hao do dimg PT tiong thoi gian sura chtta bg phan thii i cSn phai dugc tinh vao gia thanh chung Cy., neu chi c6 chu ky siia chfta ciia bg phan nay Ion ban, so voi chu ky cdc bg phan khde dong thai dugc phuc hii vai no, nhung c6 cdc tuoi thg nho ban.
Cdc chi phi cho giai the, ldp rdp va ISp dat cum may, ma bg phan i true thu6c, can phai dua vao hoac hoan toan kh6ng dua vao gid thanh phuc hoi ciia no tuy thudc vao vi8c cdc bg ph^n khde CO thugc vi cum may nay hay khdng vd sir kh6ng the siia chiia no song song v6i cdc bg phan khde.
Do v§y, khi bg phan / dugc dua vao cau tr^c cua chu trinh sira chiia, chi phi cho viec phuc hii no CO the thay doi trong cdc gidi b^n ttr C^^, den C y , nghia la Cy^,- ^ C, < Cy^.
Xuat phdt tii quan h8 chu ky sira chiia ciia cac bg phdn ri6ng bi^t va sg true thugc ciia mii bg phan vao cac cum may, ta thiet ldp mgt thudt todn hinh thanh cdc gid thanh phuc hii cac bg phdn nhu sau.
Gidsiirdng e^ =||/j,,,/j,2,...,/^,...,/j„||-labg cdc tuoi thg gamma-phan tram, bo tri theo thii tu tang dan ciia chiing, co nghia la
Ngoai ra, ta dua vao cdc bg dfl- lieu sau ddy, ma cdc phan tii cua chiing ciing se phan b6 theo thii tu tang dan cua cdc tuii thg cua cdc bg phdn tuang ling:
- Cac so hieu ciia cac cum mdy, ma cdc b6 phan true thudc nd:
H = \\H,,H2,H^,...,H„...,H,\\;
Cac chi phi vi8c phuc hoi true tiep cdc b^
phdn;
-P.
^Jhl! ^flii '—' ^Jh, '—J ^JhnlCdc chi phi cho cdc cdng viSc ISp rdp- giai the cac cum may, ma cdc bd phdn tuang ling true thudc nd (tiong do cd cdc bg phdn sua chiia tuang ling):
Cac khoang thcri gian phuc hii cac bg phdn:
t = \\t„ty„...,t,-,...,t„\\.
Niu biit cdc tdn hao do dung PT h-ong thdi gian 1 gid la C,j,ta dugc bO cac tin hao do dCmg
PT trong khoang thdi gian phuc hdi cac bg phan tuang iing:
Thu§t toan hinh thanh cdc gia thanh phuc hoi cac bd phan, ma tudi thg ciia chiing dugc su dung de xdc dinh cdu triic tdi uu ciia chu trinh siia chiia bSng phuang phdp quy hoach ddng, dugc xdy dung blng cac phuang phap Idgic todn hgc. D i lam dieu do, tap hgp M cua cac bg phdn dau may, ma theo tudi thg ciia chiing xac dinh cau tnic cua chu trinh sua chiia, dugc biiu diln dudi dang cdc tap hgp con Mj va M2, ddng thdi M=M,+ M2.
Tap con Mj Id sd cdc bd phan, ma khi phuc hdi moi bd phan trong sd do khdng cho phep siia chiia cdc bg phan khac (vi du ti6n bang-da banh xe ma khdng day ra khdi dau may): Mj{l,2,..., k,..., Nl}. Cdc tdn hao do diing PT trong thdi gian sua chiia cac bd phan nam trong tap con nay hoan toan dua vao tiong gid thanh phuc hdi cua chiing.
Tap con M2 - la s i cdc bd phan, ma viec phuc hdi cua chiing cd the tien hanh mgt each song song: M2{1,2,..., k,..., N^}, ddng thdi A'' = Nl + JV^- Khi phuc hoi mdt sd bg phan trong tap con M2 d mdt trong cac cap sua chiia tdn hao do diing PT chi can tinh cho bg phan cd thdi gian sica chiia ldn ban.
Den lugt minh tdp con M2 dirge chia ra r tap con niia theo miic do true thugc ciia cac bd phan rieng biet vao mdt trong cdc cum may:
m^,m2,:;m^,...,m^. Co H^bd phdn true thugc cum may s tix tiong tap con M ; , m^ =\\,2,...,g,...,n^], ddng thdi Hj + H 2 + — + Wj -\-... + n^ = N2.
Su hinh thanh cdc gia thanh phuc hdi cac bg phdn dugc diln ra nhu sau:
Niu mdt bd phan thudc v i tap con Ms, thi trong gid thanh phuc hdi cua nd bao gdm toan bg cac tdn hao do diing PT trong thdi gian sua chiia nd, cdc chi phi cho giai thi vd ldp rap cum may ma nd chiia bd phdn da cho, cd nghTa la
Ddi vdi cac bO phdn lien quan din tap con MJ , cac gia thanh phuc hdi chung duac tinh theo mdt each khde. Vi rang tdt ca cdc bd phan cd tudi thg gamma-phdn tram {ly) ldn hem bao gid ciing dugc phuc hdi mgt each ding thdi ciing vdi mgt bd phdn, ciing tu cum may dd, ma cd tudi thg ly nhd ban, nen gia thanh cac chi phi cho cdc cdng
viec ldp rap-sira chiia chi dugc xet den trong gid thanh phuc hdi bg phan cd tudi thg ly nhd han.
Cac tdn hao do diing PT tiong tiidi gian phuc hdi cac bd phdn cua tap con Mj cflng dugc xac dinh xuat phat tir chd la cdc bg phan cd tudi thg ly ldn hem bao gid ciing dugc siia chiia ddng thai vdi cdc bd phan cd tudi thg ly nhd han. Vi vay cdc tdn hao do dimg PT trong thdi gian sica chua t^ cua tap con thii nhat Mj, cd tudi thg nhd hem, cdn dugc dua toan bg vao gid thanh pbiic hdi cita nd:
^'1 =<^fhl+^r-h
Bd phan thii nhat ed tudi thg nhd nhat trong so cac bg phan eiia tap con M j , vi vdy cac chi phi cho cac cdng viec lap rap-giai the bao gid cflng bao ham trong tiong gid thanh phuc hdi c ^ nd:
^l ~ ^M "*" ^M "•" ^r -h
Trong gid thanh phuc hdi cdc bd phan cdn lai cd tudi thg ldn han, thudc v i mdt cum may, ke ca bg phan thii nhat, khdng bao ham cac chi phi tuang tir.
Neu trong tap con Mj khdng cd mgt bd phan nao cd tudi thg /y^ldthhan va thdi gian sira chiia ldn hon so vdi bg phan thii nhat, thi cae tdn hao do dimg PT trong thdi gian phuc hdi chiing khdng bao ham tiong gia thanh phuc hdi chimg, vi chiing da dugc tinh den tiong gia thanh phuc hdi ciia bg phan thii nhat. Trong trudng hgp nay, khi thdi gian phyc hdi /jcua bd phan kd tiep k \)<k<N2j theo thic tu tang dan cua tudi thg ly cua tap con M , ldn ban thai gian sua chiia /, cua bg phan thii nhat, phdn tdn hao phu, do khoang thdi gian siia chiia ldn hem ciia bg ph^n da cho so vdi bg phan thic nhdt, can dugc dua vao trong gid thanh phuc hdi bg phan thii k da cho:
Q =C^^+C,(r^-f,), ddng thdi \<k<N^
Tuang tu, ta xac dinh cac chi phi cho viec phuc hdi cac bd phan tiep theo ciia tap eon M j , cd tudi thg ly ldn ban so vdi cac bd phan ma cdc gid thanh cua chiing da dugc xdc dinh. Ndu nhu thdi gian sira chiia /^ cua bd phdn ke tiep cua tap con M^nhd han thdi gian phyc hdi ^^cua bg phan z trudc dd ciia tap con M^, ma trong gia thanh siia chiia cua nd da dugc tinh tdi cdc tdn hao do dimg PT tiong thdi gian sua chiia, thi cdc tdn hao do dimg PT trong thdi gian siia chira bd
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Journal of transportation science and technology, Vol 15, May 2015
phan thii k khdng dua vdo cdc chi phi chung cho viec phuc hdi bd phan dd:
Q =C^^,ddngthdi l<z<k.
Khi t^ < t^ cdn phai tinh tdi trong gid thanh phuc hdi bd phan k mdt phdn cdc tdn hao, gay ra bdi thdi gian phyc hdi cua nd ldn ban va chua dugc tinh den trong gia thanh eua eac bd phan trudc cua tap con M j .
Gid thanh phyc hdi bg phdn k:
Q =C>i +C'rfe - / J , ding thdi l<z<i.
XSy dung thuat toan tinh toan tren MTDT bdng tiin hanh hinh thiic boa nguyen tic hinh thanh gid thanh phyc hoi tiing phan tii thic i ciia tap hgp M [3]. Cac phucmg an cd the ve hinh thdnh cdc gid thanh la kha vi nhd cae bien Idgic sau ddy.
Biin X|(/) cho biet sy true thudc cua bg phdn ivao mgt trong cac tap hgp con M,va M2(bg phan i thudc vi mdt trong cac tap hgp con Ml va M3). Bien X, [i] nhan gia tri 1, neu bd phan dd cho thudc vi tap con M^. Neu nhu bg phan nay la tic tap con Mj, thi X^ (i) = 0
Bi8n X2 {kj = 1, neu bg phan cd tudi thg ly la nhd nhat trong tat ca eae bg phan ciia tap con M2 vdi A = 1 (tiong dd A - sd hieu ciia bd phan ciia tdp con M^, ma dii vdi nd gia thanh phyc hdi dugc xac dinh).
Bien X^ [k, y) = 1, neu bg phan k cd cd tudi thg ly la nhd nhat tiong tat ea cac bd phan cua tap con Afj, ma nd thudc ve, ngoai ra, cimg mgt cym may.
Neu tir cac bd phdn cua tap con M j , duge bd tri tiong thii tu tang ddn cua tudi thg ly cua chiing, du chi mgt bd phan thudc ve cung mdt td may m^, cflng nhu bg phan k da cho, nhung cd tudi thg ly nhd nhat, thi X^ {k, j) = 0, tiic la
[1, niuy e m^vdi k em^, 0<k <j [0, neu J G m^ vdi k em^, 0<j<k Bien X^ [k, z) = 1, neu thdi gian phuc hdi bd phan A: ciia tap eon M^ ldn han thai gian phuc hdi ddi vdi mdt trong cdc bg phan z cung cua tap hgp con Mj nay, ma cac bg phan nay cd tudi thg ly nhd hem tudi thg ly d bg phan k. Cdn
^ 4 , itj) -
niu nhu t^ <t^(0 < z <k), thi biin X^(A:,z)=0,tiiela:
nm^ < t^,
(vdi keM2,zGM2,0<z<k,k>l) Td hgp eac biin Idgic, xdc dinh cdc phuang dn cd th8 cua gid thanh phyc hdi eiia mdt bg phan dugc gidi thidu trong bang 1.
Cdc chi phi eho viec phyc hdi bd phdn thir i cua tap hgp M dugc xac dinh tuy thudc vao td hgp cdc gia tri cua cac bien Idgic, ma tren ca sd dd, thanh lap duge mgt thuat todn hinh thdnh cdc gia thanh ciia cdc bg phan (hinh 2), va dua vdo thuat todn tinh todn cau tnic tdi uu ciia chu trinh sua chiia.
Bdng 1. TS hop cdc biin logic Giatr
^1
0
-
0 0 0 0
ciia cac bifin 16gic X!
1 0 0 0 0
X,
- -
1 1 0 0
X4
- -
1 0 1
C6ng thiic xdc djnh cac chi phi C Cftl+C;„+C,.(, Cfh&Cir&Cr.ti
Cfhi+t:in CfU+Ciri+Crfti-tJ
Cm Clhl+CCk-tz) Viec tinh toan dugc bat dau tir cae s6 Ii$u ban dau di tinh toan he thing sua chfl'a tdi uu la cac gia tri cua eae tudi thg ly cua cac bO ph^n bj hao mdn va cac gid thanh phyc hdi cua chiing.
Cac bd phan dugc xem xet dugc bd tri theo thii ty tang dan cua tudi thg va quang dudng chay ea sd Z,;, cd nghia la guang dudng chay ciia bd phdn cd tudi thg nhd nhat, dugc cd dmh.
Quang dudng chay ca sd cd thi thay ddi tiong pham vi 0,5. //, </,/<//, ....
Cdc tinh todn dugc thuc hien bang phuang phdp quy hoach ddng [4] d cdc gia tri khde nhau cua quang dudng chay ea sd, bat dau tir gia tri nhd nhat va sau dd dan dan thay ddi nd theo dai lugng cua budc A/.
Viec xac dinh quSng dudng chay giuia cdc lan sica chua ciia dau may, khoang thdi gian lam viec cua thiet bi gifla cdc lan hu hdng dugc thye hien vdi do chinh xdc tdi 1000 km, vi vdy gia trj ban dSu L^ dugc ldy la mgt sd nguySn gan nhat vai 1/2 vdi cd du, tiic la £,[0,57, -I-1].
Sau khi tinh todn cdu tnic tdi mi ciia chu ky siia chu'a d i , cd dinh va xdc dinh cac chi phi dan vi tdng cdng nhd nhat O, ( i , ) cho vi?c tien hanh cac ldn sto chiia ke hoach ciia tdt cd bg phdn
dugc xem xet, ta tang L^ len mdt budc tidn hanh chgn mdt gia tij quang dudng chay giiia AL = 1000 km va tiin hanh mgt ehu trinh tinh cdc lan sira chiia cua bd phdn thii nhdti*, ma d toan mdi. do dam bao duge gid tri nhd nhdt cua tdt ca cae
Sau khi thyc hien tit ca cac budc tinh toan cue tieu quy udc ciia ham myc tieu (2).
D
Hinb 2. So do khoi thudt toan xac 3. NhSn xet vd Itit luan
Bai viit trinh bay ca sd xac dinh cdu tnic tdi uu cua chu ky su'a chua thiet bi van tai tren ea sd gia thanh sica chiia va miic tin cay cho tmdc, the hien bang tudi thg gamma-phan tram ciia chi tiet cung cac gidi thudt de thiet lap chuong trinh tinh toan cau true tdi uu cua chu ky sica chu'a ciia thiet bi van tai.
Tiip theo cac nghien ciiu [3, 4], bai viit nay cung vdi [2, 5] la phan chuan bi cho bao cao ciia de tai nghien cuu "Xdy dung phan mem Tdi iru hoa thdi han siia chiia PTVT tren ca sd dg tin cay" dugc tdi trg bdi Dai hgc Qudc gia TP HCM (VNU-HCM) trong khudn khd de tdi ma sd C2014-20-04a
Tai lif u tham khao
[1], Dd Dice Tudn. Ca sd tdi im hod chu ky sua chiia cdc chi tiet va cym chi tiet tren ddu may ed xet tdi hu hdng khdng tham sd va chi phi siia chiia. Tap chi "Khoa hgc Giao thdng Van tai". Sd 16, tr 125-136, (thang
12/2006)
[2]. D 6 Diic Tudn, Vo Trgng Cang. Ca sd TUH thdi han SC cdc bd phdn chay trgn DM TX d
dinh gia ihdnhphiic hoi cdc bo phdn
mice cho t n r d c cua D T C tham sd. T a p chi
" K h o a h g c Giao thdng V a n tai". Sd 17, ti 134-142, (thang 4/2007)
[3]. D d Diic Tuan. C a sd xac dinh cdu t n i c tdi u u ciia chu trinh siia chiia ddu mdy tren c a sd gia thanh siia chiia va tudi thg g a m m a phdn tram chi tiet. T a p chi " K h o a h g c Giao t h d n g V a n tai". Sd 2 1 , n-134-142, (thang 3/2008)
[4]. D d Diic Tudn, N g u y i n Trung Kien. T h i i t lap c h u a n g trinh tinh toan cdu tnic tdi u u ciia chu trinh sira chu'a ddu m a y tren c a sd chi phi siia c h u a va tudi thg g a m m a phdn tram chi tiet. T a p chi " K h o a hgc Giao thdng V a n tai". Sd 2 4 , tr 31-40, (thdng 1 1 / 2 0 0 8 ) [5]. V d T r g n g Cang. Tdi u u hoa thdi h a n s u a
chiia p h u a n g tien van tai tren c a sd dd tin cay tham sd. T a p chi Phat trien K H & C N , D H Q G H C M , T i 7 , K 7 - 2 0 1 4 , tr 35-44 [6]. TopcKHii A . B , BopodbeB A . A .
OnTHMHsaqHH CHCTCMbi peMOHxa TenjioBosoB. MocKoa, TpaHcnopx 1994.
N g i y n h f n b a i : 20/3/2015 ""^^'' N g a y c h a p n h d n d a n g : 14/4/2015 Phan bien:PGS.TSKH. BSng Hiru Phu
