Tu nhien, cho din thdi diem hiin nay, viec ddnh gid chdt lUdng cua rd bdt chUa dUdc quan tdm dung mik Mot trong cdc thdng so quan trgng nhdt, dnh hUdng trUc tiep den khd ndng Ung dung cu
Trang 1NGHIEN CUfU - TRAO OOl
THI^T Kg HE T H 6 N G DO D p CHJNH XAC LAP CHO RO B 6 T CONG NGHI| DESIGN OF THE REPEATABILITY MEASUREMENT SYSTEM FOR INDUSTRIAL ROBO
Nguyen Trpng Doanh TrUdng Dai hpc Bach khoa Hd Npi
TOM TAT
Xu hudng tu ddng hod qud trinh sdn xudt ngdy cdng dUdc chu y phdt trien d Viet Nam Viic i^ dung rd bot cdng nghiep thay the cho ngUdi cdng nhdn dang trd thdnh nhu cdu khdng the thiiu dUdc Tu nhien, cho din thdi diem hiin nay, viec ddnh gid chdt lUdng cua rd bdt chUa dUdc quan tdm dung mik Mot trong cdc thdng so quan trgng nhdt, dnh hUdng trUc tiep den khd ndng Ung dung cua rd bot dd cfti'w)
Id do chinh xdc lap Trongphqm vi bdi bdo ndy, tdc gid trinh bdy ve thiet kecua mgt he thongdosdu thdttl phdn dung de ddnh gid do chinh xdc lap ve vi tri vd do chinh xdc lap ve djnh hUdng cua rd hdt cdngngh^
ABSTRACT
Trend of the automation of manufacturing systems is more and more concentrated to developp b Vietnam Application of industrial robots becomes a avoidable demand However the evaluation o/ffc industrial robot's performances isn't correctly interrested One of the most important robot's parantc^
is the repeatability In this paper, autor represents a design of a measuring system with six components which is capable to evaluate the repeatability of robot in positionning and in orientation
1 DAT VAN DE
Viec ddnh gia chat lU(?ng cua rd bot cdng
nghiep khi nh^p khSu, trong qua trinh ldp dait
van hanh vd trong sil dung Id vi|c lam can thilt,
bdi nd lien quan din tinh hi|u qud ciia iJng dyng
trong qud trinh san xuat Tuy vay, cho din thdi
dilm hien nay, d nUdc ta chUa cd thilt bi de cd thi
danh gid dupc chat lUpng cua rd bdt cdng nghi|p
De cd thi danh gia dUpc chat lu^ng ciia rd bdt
cdng nghiep, trUdc hit ta phai dUa vdo cac tieu chi
ky thu^t do nha san xuat cung cap Cac lo^i rd bdt
tuy cd khdc nhau ve cau tao nhUng cdc thdng so
ca bdn deu tuong ddi gidng nhau, do la: j
- Sd bac ti^ do;
Tdc dp chuyin dOng tinh tiln, tdc dp chuyS dpng quay;
- Dp chinh xdc l^p;
- Sai sd dinh hUdng;
- Khdng gian ldm vi|c;
- Tdi trpng cUc dai
Mdt chi tieu quan trpng nhat trong ca chi tilu chdt lU(?ng cua rd bdt dd Id dd chinh xi lip cua rd bdt cdng nghiip Dp chinh xdc l?p cu TAP CHi CO KHf VIET NAM • S6 5 (Thang 5 D a m 2 0 | ^
Trang 2NGHIEN CUfU - TRAO e(!)l
rd bdt la mi5c dp t^p trung cua sai sp trpng qua
trinh dinh vi ciia tpa dd diem cudi cua rd bdt den
mpt vi tri xac dinh Theo cac nghiin cUu tii trUdc
den nay thi dp chinh xdc lap ciia rd bdt nam trong
khoang tU +0.05 m m d i n ±5mm vd khodng 70%
rd bdt cdng nghiip cd dp chinh xdc lip khdng qud
± l m m Thiet bi diing de danh gia dp chinh xdc
lg.p cua rd bdt thUdng rat dat tien vd kha nang Ung
dung Cling rat khac nhau Trpng lu^n van tiln si
ciia minh, Brethe [1] da sU dung nguyin ly truyin
thdng la khdi mau hinh hop, dupc dinh vi bdi
rd bdt vao khdi am ban cd gdn ba cdm bien dich
chuyen ^im cua Mitoyo d l xac dinh sai sd dinh vi
theo ba phUOng De xdc dinh sai sd dinh hudng
cua tiing khdp quay, Brethe tiln hanh do sai sd
dinh hudng cho tUng khdp bang mdt he thdng
do khdc Mdt phuong phdp khdc do Koseki [2] d l
xuat la Sli dung hinh anh do Ca me ra ky thu^t sd
de xac dinh sai sd dinh vi ciia vat mau vao vi tri
cho trUdc Phuong phdp nay ddi hdi thilt bi cd dp
phan giai cap va kha dat tiln Phuong phdp thii
ba do Shiakolas de xuat do la diing thilt bi do ba
chieu thdng qua cac cam biln lUc de xdc dinh sai
sd dinh vi cua khdi mau hinh tru cd khoan cdc
Id ddi xiing vd tUOng Ung vdi he Id t r l n am ban
Phuong phap nay cung cd t h i dat dp chinh xdc
khd cao, nhUng thilt bi do ciing khd dat tiln
De thilt ke mdt he thdng do dam bdo dUpc
ylu cau ddi vdi cdc rd bdt hien cd d Vilt Nam,
vile chpn phuong an thiet k l don gian va kinh
t l la viec lam can thilt HI thdng do dd chinh xac
lap kieu truyen thong la xdc dinh cdc sai sd dinh
vi cua khdi hop chuan vao am bdn t^i vi tri da
lap trinh sdn cho rd bdt, tU day, ta xac dinh sai so
v l dinh vi va dinh hUdng theo cdc phuong khdc
nhau Van d l bd tri cdm biln nhU t h i ndo, bao
nhieu cdm biln cd the du cho viec xac dinh sai sd
dinh vi va dinh hUdng, Id vdn de mau chot
Trln hinh 1 la minh hoa v l sai sd dinh vi
vd dinh hudng ciia rd bdt trong khdng gian lam
vile
- Sai sd vi tri: e^, By vd e^
* - Sai sd hudng: 6^, 9y va ^^
Hinh 1: Sai sd vi tri vd sai sd hUdng trong qua trinh dinh vi ciia ro bdt cdng nghi|p
2 BO TRf CAM BIEN VA NGUYEN LY CUA
HE THONG DO
Theo nguyin ly 6 DOF cua vat the trong khdng gian, ta can dinh vi dupe sdu bac tU do, nhU vay, Sli dung 6 cam biln la can thilt Vdi sdu cam biln vi tri, ta cd the xdc dinh dupe sai sd vi tri theo
ba phuong X, Y, Z va sai sd dinh hUdng TU sai
sd dinh hudng phai xae dinh dUpc sai sd gdc ldn nhat cua true khoi mau vdi mat phang XY Vdi sau cam biln ta cd the bd tri theo phuong an 3-2-1 Id phuong dn thich hpp nhat cho vile xac dinh cd sai sd dinh vi va sai sd dinh hUdng Theo phuong
dn ndy, cac cam biln dupe gd t r l n ba mat phang
ciia he toa dp c6 dinh XYZ, HI to^ dp ciia khoi
mau, tuong Ung vdi toa dp dilm cudi cua rd bdt
la XjYjZj (hinh 2) Gid stf toa dp ban dau ciia cdc cam bien lan lUpt la :
Si(X„,Y„,Z,,),S,(X,,,Y,.,Z,,),S3(X„,Y„,Z,3), S,(X,.Y,,Z,,), S,(X„,Y„,Z,3), S.(X3.,Y,.,Z,,) Gia thilt ba cdrh biln S^, S^ va S3 dUpc bd tri trong mat phang XOZ va S^, S^ trong XOY vd S6 trong YOZ Cdc gid tri ban ddu eua cdc cam
biln d i n khdi mau ldn luot la a, b, c, d, e va i Toa
dp cua cac diem do trln khdi mau se Id: KX,,, Y„+a, Z J , 2(X33, Y,,+b, Z,,), 3(X„, Y„+c, Z„) 4(X„, Y„, Z^^+d), 5(X33, Y33, Z,3+e), efX^^+f,
Ys ZJ
Ba d i l m 1,2,3 xdc d i n h vi tri eua m a t atl
TAP CHl C O K H i VIETNAM V S6 5 (Thing 5 nam 2012)
Trang 3NGHIEN CtfU - TRAO D 6 I
mat p h i n g X,0,Z, Ta CO the" thong qua phUdng y ^ „ 4 _ j y j ^ ^ ^ t o ^ h l p h u o n g »2 = «i dohaimjt
trinh cua m^t mjt phJng niy dl xdc djnh phUOng ^^^^^ ^^^ ^^^^^ ^^^ ^^ ^ j ^ ^ ^
trinh cua vie to phap tuyfe H, v6i mjt phSng d6:
., ^ - Vic to phdp tuySn cud mat phang ndy cd
Ml =M1J.M13
_ _ d^ng: ni =u4j.u;
Trong d6 uu.uu Id cdc vie td chi y ^ j
phuong di qua cdc di^m (1,3) vd (1,2)
Ta co:
= iX^-X^.T„+a-T„.Z^-Z„)
=(x^-x,„T^+o-r,,-b,z^-zj
= (.x» - X,, r„ -Y,,.z,,+d- z„ - i)
Vic to phdp tuyfe trin dU<?c dUa vl dang;
«3 ~UA5.U2 = ( ^ ^ : C : )
v6i: A, =
Vdi; A
Phuang trinh phdp tuyen cua mdt phang
X p , Z , se CO d ^ g : m =uii.uii = ( ^ i , S i C , )
(Y,,+a-Y„-c) (Zs.-Zjj)
''(,Y„+a-Y,,-b) ^Z,,-Z,,)
_ ( Z s , - Z j j ) (.X^,-X„)
(Z5] - ^S2 ) (Xg, ~Xs2)
^(.X,,-X„) iY„+ct-Y,,-c)
' (X^-X,,) (Y,,+a-Y,,-b)
Phuong trinh mat phdng se co dang;
{x-X„)A,+(,y-a-Y,,)B,+(z-Z„)q=0 (1)
B, =
O - ^ - n , ) (Zs4+d-Zs,-e)
B, C, (Z,,+d-Z,,-e) (X,,-X,,)
C, ^1 ( - ^ 1 4 - - ^ « ) (>'s4-»'s5)
-4, B,
s
S3
Z Zi
Phuang trinh mdt phdng X | 0 , Y , se la:
(x-XJA,+{y-Y,,)B,+{z-Z,,-d)^0 (2)
MJt phdng Y , 0 | Z , duoc xdc dinh boi hii vec ta phap tuyin cua hai m^t phdng tren vd vi Iri xdc dinh bai cam bijn thii sau Phuang trinh phap tuyen cua m$t phdng nay c6 d ^ g :
ny =n\.ni ={Ay.Bj,Cj)
f — • i L c
-_:2^0i! -.««J—•
4 ^ ^ V - y 5 / ^ Y,
Vdi: A^ •• Bl B2
A
-i^
Cl
c
Bl B;
i B , = Cl C2
A
Xl Phuong trinh m j t phdng nay se la:
Hinh 2: So dd ba tri cdm bifa trong h? tea di} c6 dinh (jc - Xjj - / ) /fj + (y - I'ss) B3 + (z - Zjs) Ci = » "
XYZ
TCI ba phuong trinh (1), (2), (3) ta cdbi Mat phang X,0,Y, xdc dinh bdi hai cdm phuong trinh:
Trang 4NGHIEN CtfU - TRAO e 6 l
A B, c,
A, B, Q
A, B, C,_ =
(4.Xj,+a.S|+a,.y,| + c,.z„)'
i.A,.X„+B,.Y„+C,.Zs,+C,.d)
(4.jr„+M+i(,.y„ + c,.z„)
(4)
'Ax
Ay
Az
=
x-x
y-y„
z-z,_
Sai lech vi tri t r l n cd ba true se dU(?e xdc
dinh bang tUOng quan sau:
(5)
Vdi Xf^,yQ,z^ Id cac gid tri ban dau eiia he
to^ dp eua khdi hop mau so vdi he toa dp co dinh
Dexac dinh cae sai sd gdc ^^-, ^, vd 0^ ta cd t h i
lay gan dung:
9y - arcsin( -) Qy - arcsin(^— ^')
y-y<i
Tuy nhien, ddi vdi rd bdt cdng nghiep,
trong phan ldn cac ung dung thi sai lech gdc 0^
chi cd y nghia trong lap rap cac chi tiet djnh hinh
Sai sd quan trpng nhat la sai sd cue dai giiia true
Z vdi mat phing XY Sai lech gdc ldn nhat dupc
xac dinh theo quan he sau: (9,^ = J\9l + 6l ]
3 CAC T H A N H P H A N CUA H £ THONG DO
He thdng do gdm mdy tinh trang bi card
A/D lOTECH: 5501MF-V, kit ndi vdi 6 cam bien
khdng tilp xiic LD701 (hinh 3) H I thdng do cd
the trao doi thdng tin vdi he thdng dilu khien ciia
rd bdt thdng qua cdc kenh sd, vUa de khdi dpng
chuong trinh thu thap dG lilu do, vUa khdi dpng
chuong trinh dieu khien rd bdt
Sau khi lap trinh cho rd bdt d i n vi tri do,
ta tiln hanh lap he thdng gid cam biln va dieu
chinh khe'hd X^, Y^, Z^ giUa khdi hop mdu va dm
ban Khe hd nay dUOc xdc dinh tuy theo cde thdng
sd eua rd bdt Sau khi dilu chinh xong, ta bat dau
khdi ddng he thdng do de lUu 1^ gia tri OFSET,
tiep den la khdi ddng rd bdt de ch^y ve vi tri gdc
va bat dau qud trinh do Phan mem thu thdp dfl lieu do cho phep ta ddt trUdc sd lan do de danh gid chat lU^ng Thdng thUdng, thdi gian chay d l ddnh gid dd ehinh xdc lap thudng klo ddi, cd nhU vlly kit qud ddnh gia mdi dam bdo dp tin cay Sau mdi ldn rd bdt dinh vi khdi hpp chuan vdo v; tri, mdy tinh se tU ddng ghi lai sd li|u do, sau do lUu l^i du! lieu va lenh cho rd bdt quay v l vi tri ban ddu d l bat dau mpt chu ky do mdi ChUPng trinh dflng lai sau khi da thUe h i | n sd lan do dinh trUdc Dfl lieu sau khi hoan tat dUpc tinh todn vd xfl ly bdng Matlab, Excel hay Access
Cim bien vi tri
""aid
A D
H e thong
£ e i i khien
ro bot
Hinh 3: So do h | thdng do Van d l lpc nhieu ciing Id van de rdt quan trpng, dac biet la trong do lUdng d mflc tan sd cao Cd the sfl dung cdc bd lpc tan sd cao hay xfl
ly nhieu bang phuong phdp sd Kit hpp ca hai phuong phdp nay cho ta kit qud rdt dn dinh Cdc cdm biln LD701 Id loai cdm biln khdng tilp xiic
cd dp chinh xdc lap ± 01mm Vdi dp phan giai 12bit, cac cdm biln nay hoan toan dii khd nang ddp Ung dp chinh xae cho ddnh gia dp chinh xac lap cua rd bdt cdng nghiep tfl cd > 0.1mm
4 KET QUA THUC NGHI$M
H I thdng do sfl dung phdn m i m vilt bdng ngdn ngii Visual Basic 6.0, da dU^e flng dung cho viec ddnh gid so bd dp ehinh xae lap cua rd bdt Pegasus tai phdng thi nghiem CIM cua TrUdng Dai hoc Bach khoa Hd Ndi
Vi tri ban dau cua khoi mau so vdi vi tri cua hei^=
TAP CHi C O KHf V I £ T NAM V Sd 5 (Thang 5 nam 2012)
Trang 5NGHIEN cdu - TRAO D6\
toa dp so sdnh la: X^= 3.678mm, Yg=3.215mm v^i
Zg=2.339 mm
Sai lech vi tri trung binh xdc djnh theo cdc
phuong nhu sau:
- Theo true X: -0.407 mm, phuong sal 0^= 0.225
- Theo true Y: -0.109 mm, Phuong sai O, = 0.216
- Theo true Z: 0.061 mm, phuong sai 0^= 0.056
Dp chinh xdc l^p dp nhd sdn xudt cung
cap la ±0.18mm Nhd vdy, n l u xdc djnh dd chinh
xae lap la ± 3 0 thi duy chi cd true Z Id cdn dam
bao ylu cau chat lUpng Hai tryc X, Y sai l|ch qud
ldn Dieu nay cung de hilu vi trong qud trinh van
hanh rd bdt da bi va d^p vdi cdc thiet bi khac vd
hon nfla he thdng dan dpng eua Pegasus lai Id cac
bd truyin xich kit hpp vdi bp truyen bdnh rang
cdn n i n bi va dap se khdng edn d vi tri dieu ehinh
chinh xac cua nd nfla
Sai lech gdc rat nhd ddi vdi true Z < 1.6"
True Y cd sai lech gdc ldn nhat < 10° va true X ed
sai lech < 2.6°
Trong thdi gian thUe nghiem cdn rat hgn
chl, kit qua thUc nghiem chUa thUc sU dam bdo
dp tin cdy Kit qud thUc nghiem thu dUpc tren ba
true X, Y, Z dupc biiu dien t r l n hinh 4
Hinh 4; Sai l|ch vj tri cua rd bdt Pegasus
4 KET L U A N
Vdi h | thdng do dp chinh xae lap cho i bdt cdng nghiip, ta cd the ddnh gid dUpc rai trong cdc ehi tilu quan trpng nhat cd liln qua
d i n hieu qud cua flng dung rd bdt trong san xua
He thdng dupe thilt ke don gian, d l sfl dung v dap flng du<?e ylu cau ddnh gid dp ehinh xdc la cho cde rd bdt cd cap chinh xde trung binh, v(M d
ehinh xac lap > 0.1 mm Do sfl dung cdc cam bii
khdng tiep xiic n i n khdng bi cdc anh h u d i ^ n^
mdn, mdi w
He thdng do nay cd the dimg khdng ch
do dp chinh xdc lap cho rd bdt, md cd the sfl d i ^ nhu h | thdng do da kenh vdi nhieu dai lupngdi ddng thdi tuy theo logi cam bien dflpc dirng, dai bilt Id trong linh vUc dao tao vd nghiin cflu
Vdi h | thdng do ndy ta ed the ddnh gia d(
chinh xdc ldp eho rd bdt mdi nhap khau vl, troni qud trinh ldp rap vd ke ed ddnh gid lai chat luoni cua cac rd bdt cu trong san xuat, de tim ra nguyli nhan vd b i | n phdp nang cao dp ehinh xdc lap ch(
rd bdt •
Tai li^u tham khao:
II] J.F.Brethe and al.; Experimental Results for Lula Repeatabilit) Measures and Comparison with the Stochastic Elipsoid Approadii
Proceeding of International Conference on Robotics and A\xW^
tion, 2004 " [2] P.S Shiakolas and al.: On the Accuracy, Repeatability^
Degree of Influence of Kinemetic Parameters for Industrial-Ro-bots; International Journal of Modelling and Simulation, Vol 21 No.part 4, pages 245-254, 2002
[3j Y.Koseki and al.: Precise Evaluation of PositioniSg Repeal-abihty of MK- Compative Manipulator inside MRI; Procedii?
of MICCAI -2004
TAP CHi CO KHf V I £ T NAM • S6 5 (Thdng 5 nam 2012)