Hoang Sinh Trirding Trudng Dai hgc Bach Khoa Ha Ndi TOM T A T Bdi bdo trinh bdy khd ndng hien thuc dac tinh dieu khien ty le analog cua cdc van servo thuy luc bdng cdc td hap van tiet
Trang 1NGHIEN CIIU-TRAO DOI
^ HIEN THL/C DAC TINH DIEU CHINH TY LE CUA VAN SERVO BANG TO HOP VAN TIET LUU THUY LL/C UfNG DUNG DIEU KHIEN KY THUAT SO
PROPORTIONAL CHARACTERISTIC REALIZATION
OF VALVE SERVO BY HYDRAULIC ORIFICES COMBINATION
USING DIGITAL CONTROL
TS Hoang Sinh Trirding
Trudng Dai hgc Bach Khoa Ha Ndi
TOM T A T
Bdi bdo trinh bdy khd ndng hien thuc dac tinh dieu khien ty le (analog) cua cdc van servo thuy luc bdng cdc td hap van tiet luu khdng dieu chinh kit hap phdn mem dieu khien bo khd trinh Vdi khd ndng loc xung, gidm chdn tdt, viec tao bd bien ddi D/A [3] dtta tren nguyen ly thuy luc Id hodn todn hien thiic
vd cd the dap dng yeu cdu dieu khien, dac biet vdi cdc he thdng qudn tinh khdng qud l&n Vai sit kel hgp ndy cho phep tao duac mot he thdng dieu khien dien thiiy lire thay the van servo vai dac tinh dieu khien tuong tu nhung vai tinh tieu chudn cao, do tin cdy cao vd vai gidm chi phi ddng ke Hieu qua se duac hien thuc bdng su don gidn cua he thdng gidm thieu phu thudc ky thudt vdo nhd cung cdp thiet bi, ndng cao dd on dinh van hdnh
TCr khoa: Ty le; Thiiy luc; Van servo
ABSTRACT
This paper presents the realization ability of proportional features (analog) of the hydraulic servo valve to the combination unadjusted orifices and a software programmable controller With the abili^
to filter pulses, better damping and converters
D/A[3J based on hydraulic principles, it sfully realized and can meet the control requirements, especialiy with the not too large inertial systems This combination allows to replace the hydraulic servo valve in a power system control having similar controls characteristics but with high standards, high reliability at^
to reduce costs significantly The effect will be realized by the simplicity similar controls to minimize tk dependence on suppliers of technical equipment, enhance operational stability similar control
Keywords: Proportion; Hydraulic; Van servo: Servo valves
TAP CHi CO KHI VIET NAM, S6 3 nam 2014
Trang 2NGHIEN cuu-TRAODOI
l.DATVANDE
Van servo thuy luc la nhung phSn tu quan
trong khdng th8 thidu trong cac he thdng didu
khidn tu ddng dien thiiy luc cd yeu cSu do chinh
xac va tu ddng hda cao Tuy nhien, khi su dung
cac loai van nay ludn nay sinh mot sd vSn dk bSt
cap [1]
Tinh tieu chuan khdng cao: Do viec hieu
i chinh didm 0 ciia phSn tu ddi hdi thidt bi va ky
thuat phiic tap va thudng chi thuc hien bdi nha
cung cap nen rdt phu thudc khi thay thd cac phkn
hi
Tinh on dinh khdng cao: Viec hieu chinh
diem 0 ciia cac phan tu nay thudng xuyen xay ra
do phu thudc kha nhieu vao dieu kien mdi trudng
lam viec (nhiet do mdi trudng, do nhiem ban ciia
dau v.v) va phan khuech dai analog thudng kem
on dinh
Gia thanh cao, yeu cau ky thuat trong bao
duong cao, chi phi van hanh cao
Nhiing bat cap neu tten cd phan nguyen nhan
ca ban do trong nguyen ly cau tao cua van servo,
bd bien ddi dien thuy lure thudng cd diem 0 khdng
dn dinh, kem theo dd do khac biet Idn ve tdc do
truyen tin hieu ciia cudn dieu khien 4 vdi tdc do
anh sang (hinh 1) va he ca thuy luc ciia thanh
truydn -ban chan 7 vdi van thuy luc 3 cd tdc do
am thanh vdi quan tinh Idn nen do dn dinh cua
he thdng bi han che Trong da sd trudng hgp thuc
te su cd thudng gap vdi van servo dd la do anh
hudng cua ma sat van 3 ma nguyen nhan chu ydu
do chit lugng dau nhiem ban, hoac dac tinh hai
vdi phun 8 thay ddi do do nhdt dau bien ddi bdi
nhiet Thuc td cho th4y, tinh ty le cua van servo
hieu qua chii ydu dd cho phep qua trinh khdi ddng
va qua hinh dung cua ca ciu chip hanh dugc dieu
TAP
chinh mem, giam thieu anh hudng luc quan tinh
he thong Qua trinh khi co cau chap hanh chuyen ddng vdi tdc do dn dinh, tinh ty le ciia van it cd anh hudng den chat lugng dieu khien
B
Hinh 1: Van servo 4WS2EM~6-2X/ vd sa do nguyen ly cdu tra khdng
De tranh nhiing bat cap neu h-en ma vh\ tao
dugc qua trinh dieu khien mem cho cac ca ciu chap hanh thuy luc, dac biet ddi vdi cac he thdng dieu khien chu ydu, tac gia de xuat mot md hinh
td hgp van logic thuy luc tieu chuin kdt hgp mot phan mem dieu khien thich hgp vdi bd kha trinh PLC tieu chuan cdng nghiep thay the van servo <i
CHI CO KHI VIET NAM, Sd 3 nam 2014
Trang 3NGHIEN ciiu-TRAO DOI
trong cac he thdng dieu khien cdng nghiep vdi
quan tinh khdng Idn
Nguyen ly cdu trd khdng cua van servo
Nguyen ly cua van servo tren hinh 1 -A cd the
dugc minh hoa bang cau trd khang B kem theo
Tin hieu dieu khien dien dugc bien ddi thanh dp
chenh ap suat nhd thay ddi cap van tiet luu 3 & 4
cd dang vdi phun ban chan Chinh do dn dinh cua
CO cau vdi phun- ban chan phu thudc nhieu vao do
sach dau cdng tac va nhiet mdi trudng da dan tdi
su kem dn dinh ciia van servo, kem theo la tinh dn
dinh dieu khien bi anh hudng
Nguyen ly cau trd khdng diSu khien dugc
de suat:
3.1
3.2
3.3
4.1
4.2
4.3
.4.1
P2 P3 P4 4.2 p ,
4.3 p ,
^ 4 1 — p^
^ ^ 4 3 p
Hinh 2: Sa do nguyen ly cau diiu khiin bdng td
hap van tiet luu cd dinh
Thay vi tin hieu dien diSu khien dugc bi^i ddi & khugch dai thanh do chenh ap suit giiia hai diem A & B bang 2 tiet luu dieu chinh trai chi&i nhau lien tuc hrong van servo, d day dugc de suSt
bd bien ddi tin hieu dien didu khien thanh do chenb
ap suat giiia hai didm A & B bing each thay d6i cac td hgp 02 van tiet luru 3.* & 4.* Ung vdi mfii
td hgp cap van 3.*& 4.*, ta c6 mot giatri xacdinli
dp chenh ap giiia A & B Nhu vay, vdi 3 tiet luu 3.1, 3.2, 3.3 ta da cd 3 gia tri Pi =(PA- PB) Voi
6 tiSt luu 3.1;3.2;3.3;4.1;4.2;4.3 ta da cd 9 giatrj
xac dinh ciia Pi = (PA- PB ) Bang nguyen lynay
ta cd the bien ddi tin hieu dien dieu khien thanh cac gia tri ap suat tuong ling vai do phan giai tiiy thudc sd tiet luu trong td hap Ta chon mdi nhom
cd 03 tidt luu 3.1;3.2;3.3 va 4.1;4.2;4.3; Vithuan tien khi hien thuc he thdng dieu khidn se tuong | ling vdi 03 vi tri ciia mot van phan phdi dien thiiy luc didu khidn 4/3
Bang 1.- Gid tri dp sudt diiu khiin Pi = PA -PB phii thugc td hgp 02 van tiit luru:
Tiet Imi 4.1 4.2 4.3
3.1
PI P4 P7
3.2 P2 P5 P8
3.3 j P3 P6 P9
Ta CO the tang s616 hgp 03 tilt liru nhilu toll
va ta bang each do, s5 t6 hcrp 3 tiit luu tang ISi theo cap so nhan Dieu nay, cho phep tang danglte
do phan giai dilu chinh gia tri chenh ap Pi = PA -PB, dong nghia voi viec tucfng tir cac dac tinhty
le gitta he thong dieu chinh ty le analog ciia van servo va to hop cau van tilt luu theo nguyen Ij tren hinh 2 So sanh dac tinh cua hai trudng tfl( dugc the hien trong hinh 3 diroi day:
TAP CHi CO KHi VIET NAM, So 3 nam 2014
Trang 4NGHllNCirU-TRAO DOI
A
tt
V
Pi
i l
0 1
Pi = 0.2
PB
Dac tinh ts le van servo
-N
/
/
P
(J(J%
4%
0
S a c tiDb t> 1^ bi^n' t b v c ba
/
y
\
•
PBI'O
V
=
PvFo
3
/ (PI-PB)/1
ng cau XxfS k)
^
Ka/IG
bang iiet lu j
.^m/i 3: So sdnh dac tinh ty le cua van servo vd
to hap van tiet luu thay the
Vdi 06 van tigt luu phan thanh 2 td hgp ta
cd do phan giai 9 vi tri (3x3=9) mdi chieu dieu khien Vdi 9 tiet luu phan thanh 3 td hap ta da
cd do phan giai dieu chinh den 27 vi tri cho mdi chieu dieu khien Dieu nay cho thay qua trinh bien ddi tin hieu D/A sd -analog bang linh kien thiiy lire la hoan toan hien thuc nhd do dan hdi giam chan ciia dau thiiy luc rit tdt Nguyen ly thay the tren cung cho phep dieu khien ca cau chap hanh vdi dac tinh ty le giong nhu khi diing van servo Trong trudng hgp mudn cd do phan giai cao ban, ta cd the de dang bd xung them cac
td hgp van tiet luru vdi chuang trinh dieu khien phii hgp
2 K£T LUAN
Bang he thdng cac td hgp van tiet lim thiiy luc tieu chuan ket hgp phan mem dieu kliien diing bd kha trinh PLC tieu chuan, ta cd the hien thuc dac tinh dieu khien ty le cua van servo thiiy luc Digu nay tao kha nang thay the van servo bang td hgp van phan phdi dien thiiy luc va van tiet luu tieu chan vdi ky vgng dat dugc mot sd Igi the dang
ke sau:
- Cho phep dan gian qua trinh van hanh va bao tri cac he thdng dieu khien tu ddng dien thuy luc
Nang cao dang ke do tin cay, do dn dinh
va hieu suat hoat ddng cua he thdng nhd do chdm duong ciia van tieu chuan (Trong khi van servo deu cd do chdm am)
Ha gia thanh chi phi khi van hanh va chu dgng trong siia chiia
Tuy nhien, cac he thdng didu khi§n thuy luc cdng suat lan thudng cd quan tinh Idn, vi vay khi ling dung td hgp van tieu chuan thay the, qua trinh '^
TAP CHI CO KHI VIET NAM, So 3 nam 2014
Trang 5NGHItNCirU-TRAO DOI
biln d i i D/A (digital/ analog) dugc thuc hien theo nguyen ly thuy luc nen se co anh hucmg.Vi vay, lin dung vcfi cac he thong co tai lan can nghien cuu them dgng luc hoc he t h i n g d l co danh gia dung ch; lugng qua trinh qua do khi van hanh [1].*>
Ngay nhan bai: 25/02/2014
Ngay phan bien: 12/3/2014
Tai lieu tham Ithao:
[1] POPOB D.N, Dinamic and regulation of hydro-pneb- system, Moskva -1977
[2] Huynh DJc Thdng, Ky thual so thirc hinh NXB Khoa hgc & Ky thuat (2006)
[3] Haibo Hu and Qin Zhang, Miilti- function realization of a generic programmable E/H valve using Jiexibit
control logic - IL 61820, USA
TAP CHl CO KHi VIET NAM, S6 3 nam 2014