NGHIEN cufu - TRAO Dpi
^ PHl/aNG PHAP DO XAC DjNH K H O A N C C A C H GlO'A CAC COT MOC DUNG DE HIEU CHUAN M A Y DO XA
DIEN TU* EDM TAI VIEN DO LU'GNG VIET NAM
MEASUREMENT METHODS FOR DETERMINING THE LENGTHS BETWEEN THE PILLARS TO USER CALIBRATION ELECTRO-OPTICAL
DISTANCE METERS EDM AT VIETNAM METROLOGY INSTITUTE
Vu Khanh Xuan, Biu Quoc Thu Vien Do lUcJng Viet Nam TOM TAT
Cac thiet bi do xa ^a dung ky thuat quang dien tii (Electro-Optical Distance Meter - EDM) dUdc sil diing rong rai trong cdc nganh xay dtfng, giao thong, lap may,...Chiing ci phamvi do den vdi km, dd chinh xdc den (lmm+2ppmD) vdi D la khodng each do tinh hdng mm [1]. Be ddm hao do chinh xdc, tinh lien ket chudn,.. cdc thiet hi do xa nay phdi dUOc hieu chudn de kiem tra chat luting ciia thiet hi vd hieu chudn dinh ky khi sit dting Vien Do ludng Viet Nam (VMI) dd tiln hdnh nghien cdu thiet ke vd xay dUng moc chudn thang hang tao thdnh dudng chudn (baselines) dung dl hiiu chudn cdc thiet hi do xa EDM. Mot trong nhdng nhiem vti quan trong trong qud trinh nghiin cdu thiet ke, xdy ditng dudng chudn la do xdc dinh khodng each chinh xdc gitta cdc moc chudn dim bdo do chinh xdc dat yeu cdu de ra de hieu chudn cdc thiet bi do xa EDM. Ngi dung ciia bdi viet ndy de cap den phuangphdp do xdc djnh khodng cdeh giita cdc cot moc ciia dudng chudn dung dehieu chudn mdy do xa dien tdEDM tai VMI.
Tii khoa: EDM, moc chudn, dudng chudn, hieu chudn.
ABSTRACT
The electro-optical distance metersusing optoelectronic techniques (Electro-Optical Distance Meter - EDM) is widely used in the construction industry, transportation, assembly machines ...
They have to measure up to several km range, accuracy to (1mm + 2ppmD) with D is the distance measured in millimeters [1]. To ensure accuracy, traceability,.. The electro-optical distance metersmust be calibrated to test the quality of the equipment and calibration before use. Vietnam's Institute of Metrology (VMI) has conducted research design and build pilars aligned to form the baselines used to calibrate The electro-optical distance metersEDM . One of the important tasks in the process of research design, the baselins are measured accurately determine the distance between the pillars to ensure the accuracy meet the requirements set out for calibration of The electro-optical distance metersEDM. The content of this article refers to the measurement method to determine the distance between the pilars used to calibrate electronic distance measurement EDM at VMI
Keywords: EDM, pillars, baselines, calibration.
TAP CHi CO KHi VI$T NAM, S6 8 nam 2014 www.cokhivietnam.vn
NGHIEN cufu-TRAO Ddi
1. DAT VAN DE
Tgi cac vien do litdng qudc gia cua cac nddc tren the gidi, tuy theo dieu kien thdc te cua m m h deu tU nghien cdu thiet ke va xay dung cac moc chuan thang hang tao thanh dudng chuan (Baselines) de hieu chuan cac thiet hi do xa EDM (hinh 1).
Hlnh 1: Sd d6 dUdng chudn EDM So luong cac moc chuan, khoang each gifla cac mdc chuan D^ va khoang each ldn nh£t gifla cac mdc chuan (khoang each tong) D^ eua dudng chuan ddoe tinh toan thiet ke gifla tren dieu kien thUe te ndi xay dflng dfldng chuan, dac trflng ky thuat eua thiet bi EDM.
Sau khi hoan thanh tinh toan thiet ke xay dflng cot moc theo cac yeu cau ky thuat dat ra viec tien hanh do xae dinh chinh xae cac khoang each chuan D^ la mot viec Iam h^t sdc quan trong Y\ ehinh cac khoang each nay dddc dung lam chuan de hieu chuan cac thiet bi do xa EDM. Mat khae thdng qua cae phep do eua khoang each D^, gdp phan nang eao tinh chinh xac cua phep hieu chuan thiet bi do xa EDM, ddng thdi cac phep do nay se khao sat dp trdi cua cac mdc chuan dam bao tinh dn dinh dfldng chuan.
2. CAC PHU'ONG PHAP X A C DINH KHOANG CACH GI0A CAC C O T MOC
2.1. Phflcfng phap do trdc tiep
a) Sd dyng thiet bi do chuyen dung nhU
thudc day Invar ket hdp vdi do ga, ldp do lan Ifldt do true tiep khoang each 1-2, 2-3,...6-7 gifla cac cpt moc. Phfldng phap nay thudng dupe sd dung trong thdi gian trfldc day do sd dung thiet bi ddn gian y\ thflde day Invar cd he so dan nd nhiet thap khoang 0,2 ppm/^C do dd anh hfldng cua mdi trUdng khi tien hanh phep do thap [1]. Tuy nhien, phUdng phap nay mat nhieu thdi gian chi phi eao hien nay it ddpc sd dung tai cac vien do Ifldng.
b) Sd dung thiet hi do trUe tiep, ket hdp vdi thuat toan thieh hdp de giam thieu cac sai sd tae ddng len ket qua do.
Theo phflOng phap nay cac thiet bi do xa EDM cap chinh xac cao cd the dUde sd dung trong md hinh do nay. Chung thfle hien viec xac dinh trflc tiep khoang each gifla eae moc ehuan thdng qua quy trinh do eu the ket hdp vdi viec phan tich tinh toan ket qua dd [1]. Trdng phfldng phap do ket hpp may do va gfldng do dat trflc tiep len bd ga dinh vi dat ed dinh tren cae cot moc sau dd thUe hien cac phep do theo quy trinh do cu the. Trong qua trinh do phai tuan thu theo dung trinh tU va yeu cau ky thuat cua thiet bi, ddng thdi, cae thdng so ve mdi trfldng nhfl nhiet dp, dp am khdng khi va ap suat khi quyen dfldc theo ddi cap nhat thudng xuyen.
2.2. PhUtfng phap do gian tiep
Trong phfldng phfldng phap do gian tiep khoang each gifla cac mdc chuan dupe xae dinh bang each so sanh gia tri khoang each can do vdi gia tri cua khoang each chuan thdng qua eae thiet bi do so sanh, nhU may so giao thoa V A I S A L A , giao thoa ke laser [ 1 ].
PhUdng phap sd dung giao thoa ke xae dinh khdang each gifla cac cpt moc (hinh 2) theo*^"
TAP CHf CO KHi V I £ T NAM, Sd 8 nam 2014 www.cokhivietnam.vn
NGHIEN CUTU - TRAO D 6 I
sd dd do khi dich chuyen gddng gdc phan xa do (corner cube) den cac vi tri tam edt mdc, so sanh he van giao thoa khi dieh chuyen khoang each chuan Im tfl dd xae dinh dfldc khdang each dich chuyin cua gfldng phan xa do ehinh la khoang each gifla cac moc chuan.
Phfldng phap do gian tiep sd dung giao thoa ke dat dp chinh xac cao, tuy nhien, qua trinh thUe hien phep do phdc tap, ddng thdi thiet bi sd dung rat dat tien gia thiet bi co the len den vai trieu USD.
^ g d * ^ ^
i^
Hinh 2: Sd do do xdc dinh khodng each giiia cdc cgt moc sd dung giao thoa ke laser, 1- nguon bUdc sdng chudn, 2- Thanh chudn 1 m, 3- giidngphdn xg gdc
dich chuyen [2]
3. PHtfONG P H A P D O XAC DINH KHOANG CACH G I C A C A C COT M O C DUNG DE HIEU CHUAN M A Y D O XA DIEN TU" EDM TAI VMI
3.1. Lda chpn phdcfng phap do
Dfldng chuan EDM tai VMI (hinh 1) dfldc thiet ke theo kieu Heerbrugg [1] phu hpp xu the ehung eua cae vien dd Ifldng qude gia
khac trong khu vUc va khuyen cao theo tieu chuan ISO 17123-4 ve hieu chuan may do xa EDM. Dfldng chuan bao gdm 07 c6t mdc dfldc thiet ke va xay dUng t h i n g hang, tren moi cot cd lap dat he thdng dinh tSm chinh xac dam bao dp on dinh khdang each khi dich chuyen may dd va gddng dd doe theo dfldng chuan.
Vien Do Ifldng Viet Nam sd dung thiet bi do la may toan dac chinh xae cao TC 2003, thiet bi nay ddpc kiem tra can than ve sai so thang do, sai so chu ky ngan, sai sd thang do...
sau dd thUe hien phddng phap do xac dinh khoang each gida cac cpt mdc theo cac bfldc n h u sau:
Dau tien ta dat may toan dac tai vi tri mdc A l , di chuyen gUdng td vi tri moc A2, A3, ..., A7 tien hanh do dUde eae khoang each d^^, dj3,d,^,dj^,djg,d|^; Tiep tuc di chuyen may d^n vi tri mde A2, khi dd van gifl nguyen gfldng phan xa tai vi tri A7, di chuyen gfldng tdi cac vi tri A6, A5,A4,A3, ta dfldc cac khdang each A3 ddng thdi dat gfldng tai vi tri A4, A5, A6, A7 ta do dflpc dj^, djj, d^g, d^^; Van gifl gfldng dvi tri A7, ta di chuyen may tdi vi tri A4 ta ed d^^, d^^, d^^; Tiep cac bfldc nhfl tren ta se dflpc cac khoang each cdn lai d^^, d^^, d^^. Cudi cung ta se ed 21 khoang each can do: d^^, di^, d^^, d^^, d,^, d „ , d „ . d,,, d,3, d „ , d„, d,^, d33. d,,, d „ . d,,, d„, V . d s 5 . d 5 , v a d „ .
3.2. Tinh toan xii ly so lieu d o
Sau khi thac hien phep do theo trinh tvl do nhu tren de dang nhan thay vdi 21 Itet qua do la cac gia tri d^^ ta co the thiet lap he philong trinh tuyen tinh (1) bieu dien moi quan he gifla cac ket qua do va khoang each D^ giiJa cac c6t
TAP CHI CO KHi VIET NAM, S6 8 nam 2014 www.cokhivietnam.vn
NGHIEN cufu - TRAO eOl
D, D D, D, D, D, D, D,
= < ! .
+ D + D, + D, + D, + 0^
+ D, + d, +D, + D + D
=
ni
+ D, + D + D4 d«
D =d„
He phfldng trinh tuyen _ tinh bao gdm 21 phfldng trinh tUdng flng vdi 21 ket qua dd.
He phfldng trinh (1) ta ed thebieu dien Trong do: A"^ la ma tran chuyen vi eua mdt each tdng quat: ma tran he so A.
AxD=d (2)
Trong do: A =(AJ , 1=1...n; j=l...k la mpt ma tran he s6 bao gom (nxk) phan td, he so A cd gia tri 1 hoac 0 va D=(D)j = l...n la mpt vector ed n sd hang tfldng dng vdi so khoang each can phai tinh toan. Vector d=(d|) i
= 1.. .k bao gom k phan td tfldng flng vdi soket quS do. Ma tran A la ma tran ed n= 21 hang va k= 6 cpt cac sd hang ed gia tri nhfl tren, vec- tor D_ la vector k= 6 s6 hang the hien gia tri 6 khoang each can tinh, vector d la vector cd 21 so hang the hien 21 sd ket qua do.
He phfldng trinh (1) la mdt he phddng trinh bac nhat gdm 21 phuong trinh vdi 6 an sd Dj ve nguyen tac la he phfldng trinh nay la khdng giai dflpc nghia la khdng cd tap hdp D^ thda man tat ca cac phUPng trinh (1); Tuy nhign, ta cd the giai gan dung he phUdng trinh n^y b&ng phUdng phap binh phUdng nhd nhat.
He phUdng trinh (1) dfldc bieu dien dfldi dang ma tran nhfl sau:
(4)
D = (A'^A)-'A^d (3)
Khi thfle hien phep do thed sd do nhfl da trinh bay d tren, ap dung phfldng phap binh phfldng nhd nhat ta tinh toan dfldc cae gia tri khoang each D^ gida cae mde ehuan eua dfldng chuan bSng each giai he phUdng trinh tuyen'^
TAP CHf CO KHi VIET NAM, S6 8 nam 2014 www.cokhivietnam.vn
NGHIEN CLJTU - TRAO D 6 |
tinh (1), dieu nay cd the de dang thdc hien thdng qua cac phan mem tinh toan nhd Exels hay Mathlab...
i r •' - i »«
Hinh 3: Ket qua tinh todn xii ly so lieu do s^ dung Mathlab Tren ed sd phan tich ly thuyet chung
tdi tien hanh do thfle nghiem xae dinh khoang each gifla cac edt mde cua dUdng ehuan tai VMI theo dung quy trinh, sau dd tien hanh xd ly so lieu, ket qua the hien tren hinh 3 gia tri khoang each gifla cac cot mdc D^ dUpc the hien tai bang 2 hinh 3, bang 1 the hien ma tran he so va bang 3 ket qua cua 21 lan do.
3. KET LUAN
Nghien cdu phfldng phap do xae dinh
khoang each gifla cac cpt mdc eua dfldng chuan Tai lieu tham khao:
EDM la mdt viec het sde quan trpng trong qua trinh nghien cdu thiet ke, xay dung dfldng chuan EDM, tfl dd lUa chon phUdng phap dd phu hdp vdi dieu kien thfle te tai VMI.
chdng va thuan Idi.
Viee dd, tinh tdan xac dinh chinh xac khdang each gifla cac mdc chuan la ca sd ky thuat quan trong va can thiet de dam bad d6 chinh xac cua chuan, do tin cay cung nhd tinh thdng nhat ve do lUdng cua cac may do EDM cJ Viet Nam. •
Ngay nhan bai: 05/7/2014 Ngay phan bien: 08/8/2014
Ket qua nghien edu da Ida chon dUde phfldng phap do phu hpp, xay dflng he phfldng trinh tuyen tinh bieu diln ket qua dd va khoang each gifla cac edt moc can xae dinh, tien hanh tinh toan xd ly sd lieu sd dung phan mem tinh toan de thfle hien qua trinh tinh dam bao ehinh xac gidp eho viec xd ly sd lieu dflpc nhanh
[1]. J.M. Rueger (1996), Electronic Distance Measurement, Sydney, Springer.
[2]. Petr Balling, Petr Kfen, Pavel Masika Czech M e t r o l o g y InstituteD/stuMce Measurement with fs Comb and Fourier Transform Interferometry 27 may 2011 -Prague 3rd Workshop Long Distance Measurement in air - FT comb interferometry.
[3]. IS017123-4 (2001), Electro-optical distance meters (EDM instruments); In i. Standard. Optics and Opticd Instruments - Field Procedures for Testing Geodetic and Surveying Instruments; ISO ( t h e internnational O r g a n i z a t i o n for Standardization).
TAP CHI CO KHI VIET NAM, Sd 8 nam 2014 w w w.cokhivietnam.vn
