Thiet ki cam bien lyc vdi dai do Iffn kiim soat tai trong cho cau true
D e s i g n o f Force Sensor with L a r g e R a n g e for Load Control o f Cranes Vii Vdn Quang*, VH Toan Thdng
Truang Dgi hoc Bdch khoa Hd Npi - Sd 1. Dgi C6 Viet, Hai Bd Trung, Hd Ngi Bin Tda sogn: 18-7-2018; chdp nhdn ddng: 18-01-2019 Tom tat
Nghien ciru chi tao cac he thing do loc luon nhan dugc sg quan tam dang ki cua cac nha khoa hoc. cac nhom nghien cdu tren the giai. Cac he thing nay doac xay dgng dadi nhiiu nguyen ly do ^^^'^.f^.i^^^ x '^^
ung dung trong cac linh vgc khac nhau. Trong nghien cou nay, nhom tac gia tap trung vao viec thiet ke aon glan mot cam biin Igc, dang li bao Igc loadcell sa dung cac ap dien tra di kiim soat tai trgng cho doi ^^f^9 la ciu iruc. Cam biin Igc dagc thiit ki cho phep do igc co do lan den 10000 N vol sai so tuyen tmh khong qua 2% Bai bao cung doa ra cac phan tich tinh toan cac thong si thiit ki cho phep tao ra cac cam bien Igc vol dai do khac nhau.
TCF khda. Cam bidn ILFC, loadcell, tai trong idn /Abstract
Researches of designing and producing force measurement systems are receiving considerable attention of scientists and research groups over the world. Such systems are built under various principles and applied into different industrial fields. In this research, the authors are focused on designing a simple load cell by using force tensors in order to control the load of cranes. The measurement range of the sensor is up to 10000 N, with the nonlinearity under 2%. The paper also provides analysis and calculation of important parameters, thus, it is allows to manifest various sensors with similar designs but with different measured ranges.
Keywords; force sensor, loadcell, large load capacity
I. Dat v a n de
Luc la radt ttong nhirng dai lugng rdt quan trong tiong co hgc md theo dd cac dai lugng khac nhu dp sudt, gia toe duoc tinh toan theo. Vi vdy, do ludng luc cd dnh hudng ldn trong nhigu ITnh vyc ky thuat. Nhieu nhdm nghign cuu da thigt kg che tao he thdng do lyc cho cac ung dung khac idiau [1 - 6]. Millward va Rossiter [1] da che tao he thdng do lyc nhigu thanh phan su dung cam bien bien dang sttain gauge cho cac thi nghiera tten cac kenh nude. Molland da thiet ke va xdy dyng radt he thdng do lyc 5 thanh phdn de thu nghiem ttong ham gid [2] vdi tai thiet ke tdi da cho lyc nang va lyc keo tuong img la 756 Nvk 378 N; rad men trucx, yvaz ldn lugt Id 463 Nm, 237 Nm vd 136 Nm.
Joo [5] da xay dtmg ragt quy trinh thiet ke ragt td hgp 6 phdn tir loadcell nho ggn cho cac ung dung rd hot su- dung cdu triic tam song song vdi tdi ttgng tdi da cho cdc lyc va md men la 196A'va I9.6M«. Kira [6] d a s u dung FEM dd thidt kd mdt cam bien luc/ md raen 6 bac tu do cho canh tay ro hot. Ci nude ta hien nay, nghign cira chg tao cac he thdng do lyc chua nhdn dugc su quan tdra dung muc. N. D. Manh [7] da rad phdng thiet ke va che tao edra bign lyc - md raen 3 bac ty do. Tuy
nhien, pham vi do lyc cdn nhd, 0 ^ 200 N, va chua dua ra dugc dia chi cd the ung dung cu the.
Viec giam sat va kiem soat lyc Id rdt quan ttpng ddi vdl cac mdy radc, cdc thiet bi lam viec vgi tai ttong ldn, trong do cd can true, vi nd dnh hudng tryc tiep dgn sy an todn cua thiet bi. Trong cac cau true, viec nang h^ vdt nang dugc thyc hien bdi he thdng bom dp lyc dau, thong qua radt he thdng ddy cdp vd rdng roc. Viec kiem soat luc ndng ciia cac cau true chii ydu sir dung he thdng do dp suit dau [8]. U'u didm cua phucmg phap nay la do chmh xdc gia tti tai ttgng dgng bidn diien lien tue theo thai gian va tdn dung ddi tugng do chinh la dp sudt dau ma cau ttuc su dung dg ndng ha vat nang. Tuy nhien, han che ciia phuang phap kidra soat tai trong thong qua dp lyc ddu Id bd phan cara bidn diudng cd tudi thg khdng cao Dac biet. trong digu kien cy thd a Viet Nara hien nay, viec sua chua hay thay thd cum cam bien nay rdt khd khan va tdn nhidu thdi gian, chi phi. Tuna Balkan [8] trong nghign cuu cua ramh cung de xudt phuang an sir dung dp dien ttd, theo dd, gid tti tai Irgngcd the dg dang thu duoc theo vi tti goc "dp vd do sy bien dang ttgn khdp ndi gap. Pliuong an ndy ddi ho, viec bd tri hgp !y cac dp dign tra tai nhung didm bien dang cua co cau va nd the hien mdt cdch ttuc tigp
' Dja chi lien he- Tel: (+84) 939226822 Eraail: quang.vuvani(ghust.edu.vn
T B P Khi Khoa hoc v^ Cong nghe 132 (2019) 056-060 lo^c gian tidp tdi trgng cua cau true. Viec che tao va
ing dung cara bidn sir dung ap dien ttd cho phep viec ItiSm sodt tai trgng cua cdu true dugc rad-dun hda, theo 36, viec bao dudng siia chfla he thdng ciing ttd nen khd thi vd dl dang ban.
Bai bao nay trinh bay mdt thiet ke vd cdc tinh todn cho cam bidn loadcell su dung dp dien trd vdi dai do lire tac dgng true tiep tir 0 den 10000 N. Viee bo tri cam bign dudi lyc ty cua rdng roc mang day cap keo vat n^ng cho phep ung dung cdm bien vdo he kiera soat tai ttgng ldn ban nhieu so vdi dai do luc tac dgng tryc tiSp. Thiet ke dam bdo do vflng chdc cua edra bien khi tai trpng dat tdi da. Cac dp dien tid dugc dan tai cdc vi tri l6i uu tten than cdm bien - noi sy bien dang xdy ra ro rSt nhdt, gnip tang do nhay eiia cam bien va dam bao dQ phi tuyen cua edra bien khdng vugt qua 2 %.
2. Thi^t k§ cam bien
Lgi dung nguygn ly nang vat nang cua cau true, cam bien duac thiet ke bd tri chiu dp lyc ciia rdng roc dudi tac dung eiia sire cang day cdp keo vat nang (Hinh
Hinh L So dd bd tri loadcell dudi tac dung cua lye cang ddy cua cdu true
/ He thong dp li.rc ddu keo giic ddy cdp 2. Rong roc co dinh lap tren than cdu true.
i. Rdng roc co dinh ddt ty len thdn cdm bien lifc 4. Cdm bien luc.
5, Tai IrQng cdn ndng M
Theo sa dd bd tti cam bidn, loadcell thay vi chiu
!ac dung tryc tigp ttgng lugng ciia vat nang M, vgi gia Ihiet sy co dan ciia ddy cap la khdng dang ke, lyc tdc dung Ien loadcell F„ dugc xdc dinh :
Fff - 2 7 sin (2
Trong do: T- lyc cang day, biing trgng lugng ciia vat ndng; M- khdi lugng cita vat nang; g- gia tdc trgng
•nidng; a - gdc nang day,
Nhu vay, thay vi do tiyc tidp ttgng lugng ciia vat n|ing, vdl viec thidt lap gdc ndng day a hgp ly, cam Wen loadcell dugc thiet kd vdn co thd dp dung cho cac
hd giam sdt tdi trong ldn ban rat nhieu so vdi ddi do han chg ciia edra bien.
Hinh 2 the hien mo hinh 3D ciia cdm bien loadcell vdi dang 2 ddm cd dinh ddi xirng nhau. Md hinh cd k i t cdu don gian, khdng ban che viec thiet ke cdc bd kich thuoc nham phuc vy cac nhu cau tdi trgng Idn tiiy y.
Luc ty cua rdng rgc tac dgng vao chinh giua mat tien ciia loadcell. Bdi vi cd 2 ngam nam deu 2 ben cho luc tac dung len giua than loadcell, luc se chia deu cho 2 ngam, do dd rad hinh cd do ciing vung cao hem. Viee lap dat loadcell tren raat phang tao the chac chan va dn dinh cho loadcell IVId hinh thidt ke tao ra 2 cap keo nen tren thanh darn gidng nhau nen cd the sir dung cdc ap dien trd de thu dugc sy bien dang cua thanh ddra.
Bdn dp dien trd sttain gauge se duoc dan lgn 4 vi tti ung vdl cac virag keo nen ldn nhat trdn loadcell, sau do ket ndi mach dien theo nguyen ly mach cau Wheatstone de thu dugc do nhay tdt nhdt
Hinh 2. Md hmh 3D cua cam bien loadcell 3. Xay dirng md hinh tinli todn thi4t ke cam bien luc
Myc ndy dua ra cdc phan tich tinh todn nham xac dinh do bidn dang ciia loadcell khi co lyc tac dyng va dua ra cac thdng sd hinh hoc, cac vi tri ly tudng cho viec dan cdc ap dien ttd.
Mdt sd ky hieu diing trong tinh todn, tuang ung cac thdng sd hinh hgc dugc md ta d Hinh 3.
E - Md dun Young, N/m^.
F - Luc dat lgn ddm vao diera cudi, N.
Fo^erioad - Lyc qud tdi ldn nhat. A'.
Fraimg - Luc danh gia ciia loadcell, N.
M- Md men dat len dam tai diera cudi, Nm.
Mh(x) - Md raen dat tien ddra tai khoang each x, Nm.
/ - Md men qudn tinh, kgm^.
H - Chidu cao cila ddm, m.
L - Chigu ddi ddra, m.
b - Chidu rgng ciia ddm, m.
h- Ty le gifla chigu rdng ddra b vdi chieu dai ddm L.
d- Chidu dai ciia 2 thanh ben vd ddm giua, m.
t - Chidu day ciia dam , m.
Tap chi Khoa 1
Hinh 3 . Cdc thong so kich thudc hinh hgc ttong thiet ke loadcell
Viec xdc dinh cac thdng sd hinh hgc dugc thuc hien thdng qua viec tinh todn chuyen vi ldn nhdt ciia loadcell khi chiu tai ttgng tdi da, sao cho, ddra ttr do d giira cao hgn dara hai ben mdt luang dung bang chuyen vi ldn nhat nhara chdng qua tdi.
Hinh 4 the hien sg do bigu dien dp bien dang udn cong cita radi dam [9], Theo dd, radi dara duac chju radt luc F/2 va M i a rad raen diem cudi, Md men udn tien ddra img vdi gia tri x chay ttr 0 ddn L dugc tinh theo cdng thuc : M , (x')- — Fx--M. Phuong trinh vi
" 2 phan chuyen vi cua ciia dara, theo [10], la :
/ W = ;^(ift-J»^) (1)
vdi digu kien bien : >''(0) ~ y\V) = 0
Ddra cd mat cat hinh chfl nhdt vdi chieu rdng b, chieu ddy /, do dd rad men qudn tinh dugc xdc dinh theo cdng thiic :
CQng theo sa do Hinh 4, md men M duoc tinh g [9] :
(3)
Hinh 4, So do bien dang uon cong ciia moi dllm
KSt liop cac d i k kien y(Z,) - 0 va licli t^ban^
cua (1), tliu duoc do lech diSm cu6i ciia dam a™
y(0) b^ng:
<5»,„=-FL' (4)
Bien dang doc theo djm la mot ham theo khoang each, diroc xac dinh nhu sau ;
«w=
M,(x)l 4 £ / 2 - t ) (5) Theo cdng thiic (4), ham [(x) ddi ximg qua diem X = L/2, nhan gia tti Ian nhit va nho nhat tai hai diem mong img I = 0 va j : - i . Tai hai diem nay, gia tri bien dang £{xj bang nhau nhimg Idiac nhau ve dau. Nhu vay bign dang ldn n h i t tren mot dam xay ra tai hai diem;diSm dau va diSm cudi ciia dim. Day chinh la hai vi tri tdi tra dS bd tri cac cam bien ap dien trd.
= s(0) = = £ ( ! ) = - — (6) SEI Trong tnrdng hop lire tac dung dat tdi gioi han cua dai do cho phep i^ = F.aims, ta cd :
Mat khac cac ap dien ttd ludn ton cd mgt gid tii hien dang cho phep tdi da Caihit,- Ddi vdi cac dp dien ttd cdng nghiep, gid tri bien dang tuang ddi cho phep tdi da thudng la 3 % [9]. Muc dich thiet ke la ldm cbo cam bien cd dd nhay tdi da, nen ^max = raiiow, hay:
Thay (2) vao (8), ta cd :
Suy ra, chieu ddy / cua dam dugc xac dinh : (8)
(9)
3 f „ ,
(10)
• ling suiit tdi
Thay (10) va (2) vao (4) ta duoc :
(11) De dat duoc dg cimg dang
1 nhd nhat cd the. Do dd, df ^' -''•':ihdn tir bien, ' ' m ^ ' v ' n i a i d a y c h o
.:hi Khoa hoc va Cong nghe 132 (2019) 056-060 tnrdc iSnax, dd dai thanh dam L va chieu day t cd thg
dugc tinh tir:
Mat khac, vdi cau tnic cua cam bien, toan bd luc tac dung chuyen hoan todn vdo lyc gay udn thanh ddm vdi F < Fraimg- Ttong ttudng hgp qua tdi, F = Foveri^^d, phdn doi Fonrhad - Fraimg dugc dou vao thanh giua ciia cam bien.
d - Kai ,t.db
Do dd, kha nang chiu tai cua cam bien dugc xdc djnh theo cdng thirc .
(14) Tir (14), chieu dai cua hai thanh ben va thanh gifla d&\soc xdc dinh thdng qua he so khd nang chju tai cua cam bien theo raong raudn.
i/ = in-^)Fra,i„t
(15) Thiet ke cara bien phu thudc vao cdc yeu cdu ky Ihuat ve ddi do Framg, ty le qua tdi TJ, do bien dang tdi da d6i vdi dp dien ttd Eaihw Cac thara sd {h. L, l/L, d]
c6lhedugcxacdinhbdngphuongtrinh(ll), (12), (13) va (15). Chgn vdt lieu la thep khdng gi vdi E = 200 GPa, dp dien ttd cd bidn dang tdi da fa;/»iv = 3 % chidu dai dp dien trd. Bg thdng sd kich thudc hinh hgc dugc de xuat nhu d Bang I.
Bang 1. Cac thdng so thiet ke cua cara bien L. mm
40 d, mm 30
b, mm 30
/, mm 6
datas, mm 0.18 Phdn mera Ansys dugc sir dung d l kidm tra bien dang ciia loadcell vdi kich thudc va thdng sd vat lieu da cd Ket qud bigu dd phdn bd irng sudt tren thanh Siiyc thg hien d Hinh 5, Cac diem gan ngam chiu iing suat keo nen ldn nhat, ttong do: vj tri 1,4 la vitri chju keo ldn nhdt; vi tri 2, 3 Id vj tri chiu nen ldn nhat.
Hinh 5. Phdn bd iing sudt khi loadcell chiu luc tac
4. Thif nghifm kigm tra
Mgt rad hinh loadcell (Hinh 6) dugc chd tao vdi eac kich thudc dugc thg hien d Bang 1.
Hinli 6. Md hinh loadcell dugc che tao vdi ddi do 0 -J- 1 OOOOAf;, 2,3.4- Vi tri ddn dp dien trd
Cdc dp dien trd strain §auge SK-06-125DR-175 [11] dugc dan tai cdc vi tri gan ngara dugc ddn tai cac vi tri gan ngdra 1, 2, 3, 4 (Hinh 5), kdt ndi vdi nhau tao thanh mgt mach cSu Wheatstone Mach cdu dugc cung cap mdt ngudn dien 5 FDC dn dinh. Hieu dien the ddu ra ciia mach cau dugc khuech dai 285 ldn, su: dung khuech dai do lucmg INA122 [12]. So dd raach dien bien ddi tin higu dugc the hien d Hinh 7, theo do he sd khugch dai dugc tuy chinh theo gia tti ciia dien ttd RG- Thi nghiem sir dung may kigra tta tai ttgng GOTECH AI-7000M vdi lyc nen tdi da 20 kN, sai sd khdng qua 0.25 % dg kiem soat va thay ddi lyc, trong dai tu 0 den 10000 N, tdc dung len diera chinh gifla ciia loadcell vdi dien tich tiep xiic 1 cm^.
Uiah 1. So do raach dien bien doi tin hieu Gid tri dien dp ddu ra eua raach dien bien doi tin hieu tuong irng vdi luc tac dung lgn loadcell dugc the hien d Bdng 2.
Bang 2. Bang gid tri hieu chudn cho edra bien lyc vdi dai do ddn 10000 A'
Tai trong dau vao, N 1000
2000 3000 4000 5000 6000 7000 8000 9000 10000
Dien ap dau ra, V 0.536 0.917 1.287 1770 2.161 2.551 2.897 3.395 3.764 4.138
Sau khi thuc hien tuygn tinh hda dua tren kgt qua thyc nghiera sir dung phuang phdp binh phuang toi
Tap chi Khoa hi thieu, dp ddc cua dudng thing tdt nhdt (Hmh 8) - dac tiimg dg nhay cua he thdng cam bidn lyc, dugc xac dinh thyc nghiera la 4.0399x10^ VIN. Do phi taygn tren dai do khdng vugt qud 2 % (Hmh 9), Do phi tuydn xudt hien lien quan den nhieu y£u td: vi tri ddn cua cdc dp dien trd khdng chinh xdc, tinh thdng nhdt vat lieu khong dat 100%, ngudn dien nudi khdng on dinh, v.v.
Tuy nhien cac khd khan ndy d6u cd thd dugc loai bd thdng qua qud ttinh hieu chudn cdm biln, tucmg ttr nhu viee thuc hien thu nhdn cdc gia tri dien ap d Bang 2,
Hinh 8. Dd thi radi quan he dien ap dau ra vd lyc tdc dung cua cara bien
Hinh 9. Sai lech mygn tinh ciia cara bien tren ddi do 5. K i t luan
Bdi bdo da cung cap cdc tinh todn va thiet ke cho radt cam bidn luc loadcell vdi dai do lyc ddn 10000 A'.
Phdn tich tinh todn ly thuyet da dua ra bd thong sd thiet ke bgp ly tuong thich vol dai do va do nhay toi uu cho edra bien Cdc phan tich nay cung cho phep tao ra cdc edra bien vdi thiet ke tuong tu vdi dai do lyc thay ddi, Thyc nghiera vdi md hinh cdm bign dugc che tao cho thay, do phi tuyen ciia cam bien dugc kiera soat d rauc dudi 2% tiong toan bg dai do vdi do nhay 4.0399x10"' VIN. Thidt ke dan gian va cdc thdng sd do lyc cua cam bien phii hgp vdi vigc lap dat tren cac thiet bi cdu true
sii dung he thong rdng rgc, day cdp nang ha vat nang.
,.a ap lyc ddu de
Nghien cuu dugc hd trg bdi dd fai ma so 12Uib- PC-072 - tmdng Dai hgc Bach khoa Ha Ndi.
Tai lieu tham khao
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[3] R.A.B. Almeida, D.C. Vaz, A.P-V- Urgueiia, A R.
Janeiro Borges, using ring sttamsensors to measure dynamic forces in wind-tunnel testing, J. Sens.
Actuators A185 (2012) 44-52.
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32 (2002) 125-133.
[6] G.S. Kim, Design of a six-axis wrist force/moment sensor using FEM and its fabn cation for an intelligent robot, J. Sens. Actuators Phys. 133 (2007) 27-34
[7] N. D. Manh, P. P, Khanh, B. V. Trung, B. V. Thanh va P, X. Khai, Mo phong thiet ke va che tao cam bien lire - momen 3 bac tu do, Hgi nghi khoa hoc kJ thuat do luong toan quoc lan thii VI, ngay 21 -22 thang 5/2015, Ha Ngi.
[8] Tuna Balkan, A load conttol system for mobile cranes.
Mechanics Research, Vol.23, No.4, pp. 395-400,1996.
[9] Farhad Aghili, Design of a load ceU with large overioad capacity, Transactions - Canadian Socie^
for Machanical Engineering 34 (3), 2010 [10] LeNgoc Hdng, Le Ngoc Thach, Siic bSn vat lieu, Nba
xuat ban Khoa hoc va Ky thuat, thang 10-2017, [li] Datasheet strain gauge N11-FA-5-I20-11 [12] Datasheet khuech dai do lirong 1NAI22.
