Những cơ sở nền tảng của điều khiển chuyển động

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C6NG NGHE

LTNG DUNG

Nhiimg cd sd nen tang cua

Position Cunent

l i

I

Amplifier

^

^^^B-

Mechanical

t

Feedback
Device

Position

Hinh 1. Bd dieu khien chuyin dong la trung tam ciia he thong dieu khiin chuyin dong.

Cac yeu cau cua dieu khien

chuyen dpng

odng ed thdng dung nhat trong mdi
tru'dng edng nghiep va mdi tru'dng nhung
la ddng ed bddc, ddng cd ehoi than va
dpng ed DC khdng chdi than, tuy nhien
edn ed nhieu li/a chpn khac. Moi ddng ed
ddi hdi cac tin hieu dau vao rieng giiip lam
quay ddng cd va chuyen dien nang thanh
ed nang. Xet d nghia rdng nhat, dieu khien
chuyen ddng giup ban sd dung ddng cd

nham dap dng tdt nhat cac yeu cau dng
dung cua ban ma khdng can phai giai
quyet tat ca cac van de truyen tfn hieu cap
thap can thiet de lam quay ddng cd.

Ngoai ra, dieu khien chuyen ddng tao
ra cae ehde nang cap cao, do dd ban cd
the thi/e hien eac dng dung tiiy chinh mdt
each cd hieu qua di/a tren viec xay di/ng
cac khdi de tao ra cac giai phap thi/c hien
cac tac vu thdng thu'dng nhd dinh vi chfnh
xac, ddng bd hda nhieu true, ehuyen ddng
vdi tdc do, gia tdc va ham tdc do xac dinh.
Do hau het ddng cd du'dc van hanh
trong hoan canh tam thdi, cac cdng cu
dieu khien ehuyen ddng can thiet de thfch
u'ng vdi tai khac nhau va dieu kien thay
dd'i, ddi hdi thuat toan dieu khien xd If
phde tap va phan hdi thdng tin t d he thdng
ed khf. Cudi eung nhu'ng khdng kem phan
quan trpng, cae tac vu chuyen dpng
thddng cd y nghia dac biet va thu'dng sii 
dung may mde cd the gay hai cho con
ngu'di xung quanh. Do vay, eac ehde nang
an ninh nhu' cdng tac gidi han va cac kenh
I/O ddde sd dung de thu thap thdng tin
trang thai ddng thdi thi/c hien cac thii tue

ddng cat.

Cac thanh phan he thong

dieu khien chuyen dpng

Sd dd tren hinh 1 minh hpa cae thanh
phan thiet yeu cua mdt he thdng dieu
khien chuyen ddng.

Oac tru'ng ddi vdi dng dung cua ban la
phan mem dng dung ma ban phat then.
Phan mem ifng dung bao gdm nhieu Idp
tuy chpn. Thu'dng thi cd mdt dng dung
giao dien ngddi sd dung cung cap kha
nang tu'dng tac ngu'di van hanh. Rat nhieu
cac dng dung chuyen ddng ed cac Idp dng
dung xd If canh bao va ket ndi cd sd dO'
lieu de ndi vdi mot he thdng SCADA.
Chiing cung ed eac hu'dng dan dieu khien
ehuyen ddng dddc thi/c hien bdi bp dieu
khien chuyen ddng. Nha san xuat bd dieu
khien ehuyen ddng tao ra moi tru'dng phat

trien ma ban sd dung de phat trien phan
mem dng dung.

Vdi chi dan da dddc nhae den d tren,
bd dieu khien chuyen ddng tao ra cac
profile chuyen dpng. Di/a vao cac profile
nay, bd dieu khien girl cac tin hieu (thu'dng
la eac tin hieu ±10 V hoac tfn hieu bdde
va tfn hieu djnh hu'dng) thdng qua mot bo

khuyeeh dai, hay mdt truyen ddng tdi
dpng cd. Nhiem vu cua bd khuyeeh dai la 
du'a tfn hieu t d bp dieu khien va bien ddi
chung thanh tin hieu lam cho ddng ed
ehuyen dpng.

Khi dpng ed chuyen ddng, thiet bi
phan hoi thu'dng la mot cam bien vi tri
-dda thdng tin vi tri trd lai bd dieu khien de
ddng vdng lap dieu khien. T d cam bien vi
trf nay, bd dieu khien chuyen ddng biet
du'dc vi trf cua dpng ed va cd the suy ra
dddc van toe ma ddng cd dang ehuyen
dpng. Mac du cac thiet bi phan hdi cung
cap phan hdi vi trf, ddi khi la thdng tin
phan hoi dac biet nhu' d d lieu t d mot cam
bien ap suat hay cam bien do dp rung, can
dddc gdi trd lai bd dieu khien.

Kien true bp dieu khien

chuyen dpng

Mdt bp dieu khien chuyen dpng ddng
vai trd nhu' bd nao cua he thong dieu khien
chuyen ddng va tinh toan tdng quy dac
ehuyen dpng theo yeu cau. Bp dieu khien
chuyen ddng sd dung cac quy dao ma no
tinh toan de xac dinh lenh momen xoan
thich hdp de gdi tdi bp khuyeeh dai dpng
cd dong thdi gay ra chuyen dpng. Bp dieu

Trajedtory Generation 
(ms) 
Supwvisory Conlrol

(ms) (with Interpolalioii) Control Loop (MS)

UO

Updates Tra|ec<ory 
Generator Basa>d on

VO And User

Response Sensot

Hinh 2. Klin true bo dieu khiin ehuyen dong

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_UUNU NCiHt U N G D ^ N G

dieu khien cliuyen dong

Hinh 3. Cae bo dieu khien chuyin dong plug-in DSP-Based

Hinh 4. Cae bq dieu khien chuyen dong tiiy chinh sir dung LabVIEW NI 
SoftMotion Module

khien cung phai ddng vdng lap dieu khien
va quan li dieu khien giam sat bang each
giam sat cac gidi han va diem ddng khan

cap nham dam bao hoat dpng an toan.
Moi mot hoat dpng nay can phai dien ra
thdi gian thi/e nham dam bao dp tin cay,
chinh xac, on dinh va an toan cao d mde
can thiet de tao ra mot he thdng dieu
khien chuyen dpng cd kha nang hoat
ddng.

Cac nhiem vu khac nhau ma mot bp
dieu khien ehuyen dpng phai thi/c hien,
gom:

Di'eu khien giam sat - Cung cap

chuoi lenh va sd phoi hdp can thiet de

thdc hien cac hoat ddng cu the nhd sau:
- Khdi tao he thdng.

- Quan li Sl/ kien
- Phat hien loi.

Tao quy dao 
Vong lap di'eu l<liien

I/O

National Instruments (NI) dem den 2
each tiep can de trien khai cac he thdng
dieu khien chuyen dpng cdng suat cao:

Cac bd dieu khien chuyen ddng plug-in
DSP-based cho PCI hoac PXI.

Cae bd dieu khien chuyen ddng sd
dung NI LabVIEW NI SoftMotion Module

Bd dieu khien chuyen dpng

plug-in DSP-Based

NI cung cap cae bd dieu khien chuyen
ddng plug-in t d cac bd dieu khien cdng
suat cao dap dng cac yeu cau phdc tap
den cac bd dieu khien chuyen ddng chi phf
thap hdn phuc vu cac dng dung chuyen
ddng diem tdi diem vdi cdng suat manh
me. Oe dam bao tdc dp cap nhat servo cao
tdi 30 kHz cho cac dng dung cd dp chfnh
xac cao, cac bp dieu khien nay sd dung
kien true bd xd If kep. Hai bp xd If nay, mdt
la bd xd If trung tam (CPU) va mdt bd xd
If tfn hieu sd (DSP), tao thanh "xUdng
sdng" cua bd dieu khien chuyen ddng NI.

Bp dieu khien CPU la mdt bd vi dieu
khien 32-bit chay he dieu hanh da nhiem,
thdi gian thUe, nhung. Bd CPU nay cung
cap cdng suat va si/ chinh xac can thiet de
dap dng hau het cac nhu cau dng dung
chuyen dpng phdc tap nhat. CPU xd li cac

lenh, ddng bd hda host, tu'dng tac I/O, va
giam sat he thdng.

DSP cd nhiem vu chinh la ddng thdi
dieu khien vdng lap kin vdi vi tri, quy dao
tren nhieu true. Nd eung ddng cac vdng
lap vi tri va van tdc, tri/c tiep dat lenh
momen xoan cho bp truyen ddng hoac bd
khuyeeh dai.

Bp xd li dieu khien chuyen ddng nay
du'dc giam sat bdi mdt bp dinh thdi giam
sat, la mot phan cdng ma ban sddung de
t i / ddng dd cac loi phan mem va reset bp
xd li neu cd sd cd xay ra. Bp dinh thdi giam
sat kiem tra hoat ddng cua bd xd li. Neu
phan chu'dng trinh tren bd dieu khien

(Xem tiep trang 22)

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CdNG NGHE

U'NG DUNG

Quyet djnh cdng tac

Nhan vien ky cdu cua DuPont cho hay giong nhd template hoac Id trinh cho
ket cau cua cac doanh nghiep, CPAS da that sd la mdt cdng nghe rat hdu ich,
dat mde 3 cua Model ISA95, bao phd thiet bi nha may thdng qua hoat dpng
va dieu khien qua trinh san xuiit. Chinh viec tap trung vao sd cdng tac da khien
cho cdng ty DuPont dat dddc tinh thdc thi khi trien khai he thdng dieu khien
phan tan tren khap the gidi, do vay: "mdt ai dd cd the van ngdi d van phdng

tru sd ma van cd the quan sat va nhan dddc thdng tin cung vdi thdng tin t d
doanh nghiep tren cdng mdt man hinh". Woll cung nhan manh v'e tap trung vao
diem manh cua CPAS. "Chung ta cd the ndi ve cdng nghe- 5 di'eu bat ky, thdng
tin xd ly chung va tiit ca vat lieu khac". "Tuy nhien muc dich sd mdt eda CPAS
la thuc day viec phan phdi dng dung gidp cho khach hang cd the thu ve ldi
nhuan".

Tiep theo la gi?

Mai sau thi Woll cung da chuyen sang chu de ve viec md rpng tam nhin cho
CPAS va ARC dddc ky vpng la se cdng bd ban nghien cdu v'e CPAS 2.0 ra thi
trUdng tac gia la Woll vao dau thang 7 nay.

Woll cho biet, hdn 20 nam qua, cdng nghe t d ddng hda qua trinh da dat
dddc nhieu tien bd, nhdng khdng he cd cuoc cai to nao dien ra, va khach hang
sd dung mai sau mdi dat ra cau hdi ddi vdi ARC la hp ky vpng gi vao the he
tddng lai eda tdddng hda qua trinh. Ndi dung cua ban bao cao CPAS 2.0 nham
tra Idi cau hdi dd. Ban bao cao dda ra cai nhin chi tiet v'e nhieu tien bd tien
doan trddc "dieu chdng ta nen can nhae la cude each mang diln ra t d nhien".
Hien nay, khoang 75% thdi gian chet cua thiet bi xay ra do ngddi sd dung
khdng dn vao tin hieu t d thiet bi cung ciip. Thiet bi thdng minh cd the bao khi
nao thi d tinh trang tdt va khi nao thi bi loi. "NhUng dieu dd chda dd tdt", Woll
cho hay. "Chung tdi tin rang nhdng thiet bi thdng minh se cd kha nang ndi vdi
ban rang chung cdn d tinh trang hoat ddng tdt trong bao lau nda va dda ra dU
doan ban se cd the tin vao ket qua ma chung dda ra trong bao lau nda".

Hien nay, tren thi trddng cd mdt sd ddng san pha'm dap dng yeu cau sd
dung SEVA hoac edng nghe t d danh gia, dda theo tieu chuan BS-7986 cua
Vien Tieu chuan Anh, Woll ndi. NgUdi sd dung se chd ddi sU xuiit hien eda
nhi'eu thiet bi thdng minh hdn nda trong tddng lai.

The he tiep theo cua CPAS se dda tren ciiu hinh lEC 61499 va tieu chuii'n
lap trinh, tieu chuan khdng yeu cau dich vu chia se. Oieu nay se dda ra nen
tang chuan hda de phat trien he thdng t d dpng hda cd model rieng vdi qua
trinh phan tan va dich vu dpc lap, Woll cho hay. He thdng qua trinh phan tan
se cung cap sUtUtri cho cae ngudn he thdng khac va se ho trd deu chuan edng
nghe cua FIPA.

Vdi cdng nghe nay, neu he thdng gap sU cd bat thudng thi nd se cd kha
nang tU ciiu hinh lai trong thdi gian thdc de bd lai sd bat thddng dd, va se tiep
tuc van hanh. "Oieu nay cd nghTa la chung ta se cd nhieu kha nang sd dung
he thdng tU ddng hda vdi thdi gian chet la 0" Woll chi ra. TUdng t d nhd vay,
he thdng nay se cd kha nang ciiu hinh lai de thich dng vdi nhdng sd bat thddng
dddc phat hien trong may mde ma chdng dang dieu khien, tang kha nang dn
dinh hdn.

3 budc

Chu d'e thd 3 va cuoi edng CPAS 2.0 ma Woll chia se d day bao gdm nhdng
khd khan ma ngddi sddung gap phai, hp cung chinh la ngddi can phai dda ra
nhdng thay dd'i hoac cap nhat cho he thdng ma khdng dddc ddng cat may
hoac qua trinh van hanh. Ngay nay quy trinh dd bao gdm 2 bddc la tai phien
ban phan mdi eho bd dieu khien dd phdng hoac dd thda va ap dung phan
mem dd vao trong qua trinh san xuiit. Oay la mot giai phap kha mao hiem va
"dddng nhd khdng thdc thi" Woll ndi.

"Chung tdi tin rang se ed quy trinh 3 bddc: tai phien ban phan mem mdi
cho bp dieu khien, thd nghiem van hanh de dam bao he thdng hoat ddng nhd
dd doan va khi ban da hai Idng vdi ket qua do thi ban se ap dung phan mem
dd vao trong qua trinh", Woll cho biet.

M.H (Theo Automationworld.com)

NhuTng cor sd nen tang...

(Tiep theo trang 17)

chuyen dpng khdng the thdc hien cac ehde nang
trong 62 micro giay, bp dinh thdi giam sat se
reset bp dieu khien ehuyen dpng va khdng eho
phep giao tiep eho den khi ban reset hoan toan
bd dieu khien ehuyen dpng. Dieu nay giup dam
bao hoat dpng thdi gian thdc eda he thdng dieu
khien chuyen ddng.

Cac thiet bi chuyen dpng dang plug-in
PCI-hoae PXI-based dddc thiet ke de dieu khien tin
cay va chinh xac trong he dieu hanh Windows
hoac he dieu hanh thdi gian thdc. Chung giiip
giam thdi gian phat trien thdng qua eac APIs] 
manh me va ho trd trong cac cdng cu tddng ta
nhd NI Motion Assistant. Hp dieu khien chuyei
ddng cua NI cd cdng suat cao nhiit la NI 735
Series vdi 8 true dieu khien ehuyen dpng bdd
hoac servo, I/O, va nhieu dac diem manh m
khac. Do cac thiet bi dieu khien ehuyen dpn
dang plug-in nay dda tren PCI hoac PXI, ban c
the tich hdp chung vdi nhieu loai module I/(
ddng thdi de dang ket hdp chdng vdi phan cittn 
them vao de thu thap d d lieu va x d li hinh anh.

Oe ket ndi cac thiet bi dieu khien chuyen dpng
vdi cac bd truyen ddng va ddng ed, NI eung cap
cac Ida chpn ket noi cap hoac khdi dau ndi.

Cac bd dieu khien ddng tiiy

chinh

Trong khi cac bp dieu khien chuyen dpng
plug-in vdi DSPs thfch hdp vdi nhieu dng dung,
ban can bp dieu khien chuyen ddng tuy chinh de
di'eu khien chuyen dpng chinh xac vdi tdc dp
up-date servo len tdi 200 kHz. Mot sd dng dung doi
hdi dp chinh xac va linh hoat cao bao gdm cac
may mde xd li lat mdng trong nganh ban dan hay
day chuyen lap rap cd kha nang tai cau hinh cho
nganh d td.

Cdng nghe I/O (RIO) cd kha nang tai cau
hinh eda NI dddc ket hdp vdi edng nghe NI
SoftMotion tao ra cac cdng cu phd hdp cho nha
che tao may mudn dieu khien chuyen ddng tiiy
chinh cd dp chinh xac cao vdi dp linh hoat cua
mdt FPGA. Ben canh cae dng dung cd dp chinh
xac cao, cae nha che tao may va OEM ed the sif
dung LabVIEW NI SoftMotion Module de thifc
hien dieu khien ehuyen dpng phdi h(?p da true sif
dung mdi trddng phat trien dd hpa LabVIEW tren
nhieu nen tang. Odi vdi cac dng dung ddi hdi he
thdng ben vdng va nhd gpn, ban cd the sd dung
eac bp dieu khien tdddng hda kha trinh (PAC) NI

CompactRIO. Bang each ket hdp API khdi chife
nang cap cao eda LabVIEW NI SoftMotion va cac
giao dien lap trinh truyen dpng NI C Series, ban
ed the nhanh chdng phat trien cae dng dung
chuyen dpng manh me va ket ndi hang tram
dpng cd bddc cung nhd dpng ed servo vdi
nhau.<'

M.T (Theo )

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