Giám sát công trình dùng phân tích rung trên các cảm biến gia tốc 3 chiều

ĐẠI HỌC QUỐC GIA HÀ NỘI
TRƯỜNG ĐẠI HỌC CÔNG NGHỆ




GIÁM SÁT CÔNG TRÌNH DÙNG PHÂN TÍCH
RUNG TRÊN CÁC CẢM BIẾN GIA TỐC 3
CHIỀU





Mã số: QC 08.13



Chủ nhiệm đề tài: ThS. Trần Đức Tân



Hà nội - 2009

MUC
LUC
1.
Bang giai thich cac chir viet tat
2.
Danh sach nhung
nguoi
tham gia
thirc
Men
da
tai
3.
Danh muc cac bang so lieu
4.
Danh muc cac hinh
5.
Tom tat cac ket qua nghien cuu chinh
ciia da
tai
6. BAG CAO
TONG
KET
6.1.
Dat

vanda
6.2. Tong quan cac van de nghian cuu
6.3.
Muc
tiau vaNpi
dung Nghian
cimciiaDa
tai
6.4. Dia diam, thai gian va
phuong
phap nghian cuu
6.5.
Ket qua nghien cuu
6.6 Thao
luan
6.7 Ket luan va kien nghi
6.8 Tai lieu tham khao
7.
PHULUC
DAI HOC
QLOC
GIA HA
NQi
TRUNG fA<vi iHOi-vlG UN
THO
VlEN
OGGbOOOOOgt
f^.
.i
1.

Bang giai
thich
cac
chir
viet tat
MEMS (MicroElectroMechanical System)
ERA (Eigensystem Realization Algorithm)
FRF (Frequency Response Function)
DOF (Degrees of freedom)
FFT (Fast Fourier Transform)
SHM (Structural Health Monitoring)
MAC (Modal Assurance Criterion)
PSD (Power Spectral Density)
MA (Modal Analysis)
MS (Mode Shape)
ODS,
OS (Operating Deflection Shape)
SEM (Strain Energy Method)
RPA (Rational Polynomial Approximation)
He vi
CO
dien tir
Thuat toan dac trung he thong
Ham dap ung tan so
Bac tu do
Bien doi Fourier nhanh
Giam sat tinh trang cong trinh
Dp tin cay theo phuong phap MA
Mat dp pho cong suat
Phan tich dao dpng (rieng)

Hinh dang dao dpng
Dang dp lech khi kich boat
Phuong phap nang
lugng
Xap xi theo da thirc hiru ty
2.
Danh sach nbumg
ngiroi
tham gia
thyc
hien de tai
TT
1
2
3
4
Ho va ten
Tran Due Tan
Nguyan Thang
Long
Nguyen Phu Thuy
Luu Manh Ha
Hoc vi
Thac sy
Tian
sT
Tien
sT
khoa hpc
Cir nhan

Co*
quan cong tac
Bp mon Vi
co
dien tir va
Vi he thong
Bp mon Vi co dien tir va
Vi he thong
Bp mon Vi co dien tir va
Vi he thong
Bp mon Vi co dien tir va
Vi he thong
Nhiem vu
Chii
nhiem de tai
Thanh
vian
Thanh vian
Thanh
vian
3.
Danh muc cac bang so lieu
Bang I: So sanh dp phuc tap
ciia
2 thuat
toan
DFT
vaFFT L
Bang 2: Bang danh
gia

mot so
ciraso L
Bang 3: Cac cha dp nhay 1!
Bang 4: He so suy hao
tuong
ung 3:
Bang 5:
LToc
lugng cac thong so thong
ka diing
Monte Carlo va Bootstrap 3;
Bang 6: LToc lugng cac thong so thong ke
diing
ERA 3'
Bang 7: Tan so cong
huong
tuong img
truoc
va sau hu hong
3*
4.
Danh muc cac
hinh
Hinh
1
Mot chiac
caubi
sap
'
Hinh

2
He thong giam sat
liantuc i
Hinh 3 Mode shape
ddu tian ciia cAu luc
truoc (a) va sau khi hu hai (b)
^
Hinh 4 Do dap ung rung
^
Hinh 5 Dac trung tan
s6
thu dugc diing phuong phap lap: truoc va sau khi hu hai
^
Hinh 6 So do FFT-8 diem chia 2 1]
Hinh
7 FFT 8
diem
i:
Hinh
8 FFT 2
diem
i:
Hinh 9 Phan tich FFT khi dimg va khong dimg cira so: so sanh ro pho
1^
Hinh
10 Phan tich
FFT khi dimg va khong dimg cira so: so
sanh dp
phan giai
1.

Hinh
11
Tin hieu chim trong nhiau
1^
Hinh 12 Phan
tich
FFT khi dimg va khong dimg
ciraso:
tin hieu trpn nhieu \i
Hinh 13
So
do tong quan
\t
Hinh
14Sad6kh6iMMA7260Q
l'
Hinh 15 Cam bien
gia
toe MMA7260Q
vabo
mach dieu khien
IS
Hinh
16VidilukhilnDSPIC30f4013
1^
Hinh 17
So
do nguyen
ly 2C
Hinh

18 Chuong
trinh giam sat
21
Hinh
19 So dd
thuat toan
21
Hinh 20 Ban mach vi
diau
khien 21
Hinh 21 Ban mach cam bian gia
toe
21
Hinh 22 Bp tao rung va ban mach cam bien 22
Hinh 23 He thong do rung 22
Hinh
24 May phatxung(f=
29.574Hz) 2A
Hinh 25
Kat
qua
chuong
trinh phan tich pho, F =29.9 Hz 2A
Hinh
26 May phatxungf^31.218Hz 2f
Hinh 27 Ket qua
chucmg
trinh phan tich pho, F
=
32.3Hz 2

Hinh 28 Quan sat tin hieu theo thoi gian tren kenh Z
2t
Hinh 29 Quan sat FFT
ciia
ca tap
dii
lieu thu dugc 2
Hinh 30 Tin
hieu
thu
tran
3
kanh
(da dugc triet DC) 2
Hinh
31
Minh boa
va
phan bo chuan
[11]
3(
Hmh 32 Do cac FRF
tran
mot cau true xay dung 3(
Hinh 33 Biia
chuyendung
va bp tao rung [5]
31
Hinh 34 Cay cau Alamosa Canyon [7] 31
Hmh 35 Cach bo tri diem vao/ra tren cau (a) nguyan ly, (b) mo hinh trong MATLAB 3:

Hinh 36
Tin hieu
thu dugc
tran
cac nut
(mianthoi
gian) 3:
Hinh 37 FRF thu dugc
tran
cau Alamosa Canyon, phep do
SISO
3^
Hinh 38 OS tai mode cong huong dau tien
3^
Hinh 39 OS tai mode cong huong thu hai
f^8.0698
3^
Hinh 40 Thong
so
MAC voi 2 mode da tinh toan dugc
3t
Hmh 41 FRF khi sir dung xap xi theo
dathue hiruty
3(
Hinh 42 OS tai mode cong huong dau
tian
dung xap xi theo da thirc huu ty
3(
Hmh 43 OS
tai

mode cong huong thu hai f=8.0698
(xapxi
theo da
thue hiruty) 3(
Hinh 44 Cay
c^u
1-40
tai New Mexico [8]
3 J
Hinh 45
B6
tri thi nghiem
tran c4u
1-40
[7]
3^
Hinh
46
FRF tai
niitgan
(so 3)
vamit
xa(s6 12)
3^
Hinh 47 FRF truoc luc
saihong
4(
Hinh 48 FRF
sau
khi

saihong
4(
Hinh 49 OS
ciia cau
tai cimg
1
mode cong huong truoc va sau
huhong
4(
Hinh 50 Nguyan tac phuong phap nang lugng theo
sue
cang SEM [9] 4]
Hinh
51
Nhan dang sai hong tai vi tri la nut 20 (toa dp X=2500 cm
Y=400
cm) 41
Hmh 52 Nhan dang sai hong diing phuong phap mem deo 41
6. BAO CAO TONG KET
6.1.
Dat van de
•
Cimg voi toe dp xay dung cac cong trinh cau duang, nha
xuong
.hien
nay thi a Viet
nam ciing da xay ra khong it nhimg tai nan sap cau hay sup nha. Tir do co the thay viec
giam sat cac cong trinh xay dung la quy trinh v6
ciing
can thiat.

Nhiing
thanh tuu trong
linh
vuc xu ly tin hieu khi dugc ket hgp voi cac
kian
thirc ve co hpc da cho phep xay dung cac
he thong giam sat cong trinh dang tin cay. Mot trong nhimg nguyan tac truyan thong cua
cac he thong giam sat nay la phuong phap phan tich rung. Phan tich rung dpng co tha dimg
kiem tra su hu hai cua cac cong trinh xay dung va vi tri cua cac
diam
hu hai nay. Phan tich
rung ciing co the sir dung de xac dinh su xuong cap cua cac cong trinh xay dung sau mot
thoi gian dai dua vao sir dung. Ap dung cac ky thuat phan tich rung co tha dua ra cac thiat
ka
xay dung co hieu qua, tin cay hon trong thi cong xay dung dong thoi
giiip
cho viec thay
the va sua
chixa
tai cac vi tri chinh xac.
Hinh
I Mot chiec cau hi sap
6.2. Tong quan cac van de nghien
ciru
Giam sat cong trinh (SHM) dugc dinh
nghia
nhu chuoi qua trinh thu thap, xir li va
phan tich dn lieu nham tao diau kien thuan
Igi
cho viec quan li cong trinh xay dung. Cho toi

nay da co rat nhiau cong trinh nghien cuu ve van de nay tuy nhien van con rat nhiau van
da
can phai tiep tuc dau tu nghian cuu.
Da
thuc hien qua trinh giam sat nay thi phai quan sat
dugc dap ung dpng cua he thong trong mot khoang thai gian xac dinh. Viec quan sat dupe
thuc hien nha sir dung mot to hgp cac cam bien dugc lap dat tren cac cong trinh can theo
doi.
Nhimg thong tin
vl
hu hong hien tai
(nau
co)
ciia
cong trmh se dat dugc
nhof
cac kat
qua do
luong
nay
kat
hgp voi cac phan tich thong ka.
Voi cac giam sat dai han, thong tin dau ra cua he thong giam sat se dugc cap nhat
deu dan, phuc vu cho viec theo doi tinh trang
ciia
cong trinh theo thoi gian va cac tac dpng
moi truong. Khi trai qua cac bian co bat nga nhu dpng dat hay qua tai thi SHM
dupe
dimg
nhu mot he thong giam sat "thai gian thuc" ve tmh trang cua cong trinh. Mot he thong giam

sat lien tuc
duoc
mo ta nhu
tran
hinh 2.
Cong trinh
To
horp
cam bien
Thu
th^p dSt li^u
May tinh phu
(xir li tai
cho)
Truyen khong da
a
Z3
m:^.
May tinh trung tarn
Phan tich da
U^u
va bao cao
Hmh 2
He thong giam
sat
lien
tuc
Nhung phan tich rung thuc nghiem va thong
ka
la cac phuong phap nhieu trien vpng

cho
linh
vuc SHM. Nguyan tac cua phep do la do
tran
be mat cua cau
true
cong trinh.
Nhimg hu hong se dugc xem la nhung thay doi khac biet ve dac trung he thong khi boat
dpng tot so voi tinh trang hien tai (hoac
tuong
lai).
Trong thuc te tin hieu rung dpng
biau dian
trong mien thai gian
thuong
khong phai la
dang tin hieu dieu hoa ma thuong la mot tin hieu rat phuc tap.
Diau
nay co
nghia
rung dpng
thu dugc la do rat nhiau thanh phan rung gay
nan.
Hay noi
each
khac do
la
tong hgp cua
nhieu nguon rung khac nhau.
Mot phep phan tich rung chi tot khi dii lieu sir dung la

dii
tin cay, do do thiat bi dimg
de thu thap
dxt
lieu la rat quan trpng. Co ba
loai
thiat bi co tha dimg de do luong va theo doi
rung dpng: dau do dich chuyan, bp bien doi van
toe
va gia toe ka. Moi mot thiet bi do co
mot gioi ban va ung dung riang trong do do gia toe la phuong phap tot nhat de xac dinh
lire
tir cac may rung. Cam
bian
gia toe se bien doi cac nang lugng co hpc thanh tin hieu dien.
Dac
diam
noi bat
ciia
cac cam
bian
gia toe MEMS la chat lugng tot va gia thanh re nen
da
ung dung vao thuc
ta
dai song.
Phuong phap rung co the dugc mo ta ban dau bang phuong trinh
ciia
dinh
luat

II
Newton. Trong mo hinh nay chung ta can quan tam tai ngoai luc va dap ung cua he thong
theo thai gian.
Nau
kich thich cau true boi mot xung (tuong tu nhu go mot tieng chuong)
thi dap ung thu dugc se la mot dao dpng bi suy hao. Co tha thay ro vai tro cua khoi lugng,
dp cung, he so suy hao va dieu kien bien trong bai toan nay.
Dao dong cong
huong
gay boi su tuong tac
giiia
tinh chat quan tinh va dan hoi cua
vat lieu trong cau true cong trinh. Tat ca rung dpng dugc coi la ket hgp cua luc va cong
huong. Dao dpng
kilu
luc bao gom cac noi luc,
sir
mat can bang, ngoai luc va kich thich
moi truong. Dao dpng cong huong xay ra khi cong trinh bi tac dpng a mot tan so cong
huong nao do cua cau
true.
Cac mode cong huong phu thupc vao tinh chat cua cau true
cong trinh. Cac tan so cong huong dugc xac dinh boi cac tinh chat vat lieu (khoi lugng, dp
cung, va he
s6
suy hao) va diau kien
bian
cua cau
true.
Da

thay rang khi tinh chat vat lieu
thay doi hoac
diau
kien bien thay doi thi cac mode cong huong cung bi thay doi (do chinh
la nguyen ly ca ban cua viec giam sat cong trinh theo
kiau
rung). Tat ca cac tham so rung
thuc nghiem se thu dugc bang
each
do dac trung tan so cua he thong. Dac trung tan so co
dugc khi tac dpng
len
cau
true
cac rung dpng voi tan so khac nhau (hinh 3). Tat ca cac cau
true
deu co tai 6 mode cong huong (ba tinh
tian
va ba quay).
Hinh
3 Mode shape dau tien cua cau luc
truac
(a) vd sau khi hu hai (b)
Cac thuc nghiem se dugc tien hanh
true tiap tran
cau va la minh hoa cho tinh huong
dimg phuong phap rung de phat hien thanh cong su hu hai cua cong trinh. Hinh 4 la so do
dap ung rung
ciia
mot cong trinh xay dung va hinh 5

la
minh hoa cho viec nhan dinh he
thong bi hu hai.
Giam sat rung
Kich
thich rung
nhan
t^o
thai
f)^
gian
dap ung xung
dap ung
Rung dong
do
moi
trudng
xungquanh
J
FFT
n.
thuc
f
FRF
\
Thong s6
mng:
Noi
\
- tin s6

suy
/ - h? s6
suy hao
/
- mode shape
y
Hinh
4 Do dap img rung
dB
/ \
Khong hu hai
dB
ft cac dinh gia
He thong hu hai
Hinh
5 Dac trung tan so thu
duac
dung
phuong
phap lap: truac vd sau khi hu hai
6.3.
Muc tieu va Noi dung Nghien cuu cua De tai
Muc tieu cua de tai nay la ung dung do rung cua cam bian gia toe ba chieu che tac
tren cong nghe vi co dien tir (MEMS) vao cac muc tieu dan dung. Cu the o day la sir dung
cam bien de do rung, phuc vu cho viec giam sat tinh trang boat dpng cua cau.
De dat dugc cac muc tieu tren, tap the nghian cuu cua de tai da thuc hien cac noi
dung nghian cuu dugc trinh bay cu tha trong cac muc dual day.
6.3.1 Phan tich rung diing bien doi Fourier
a. Bien doi Fourier cua tin hieu rai rgc DTFT
Xet tin hieu x(n) la rai rac v6 han, dugc lay mau tir tin hieu tuong tu voi tan so T.

Voi
Q=
o).T.
Ham DTFT dugc dinh nghia nhu sau:
X(")=
2;x(«).exp(-yQ«)
(1
Ta nhan xet thay tuy tin hieu
roi
rac trong mien thoi gian nhung DTFT lai
lian
tuc va
tuan hoan trong mien tan so. DTFT chinh la ham phirc theo
bian
tan so thuc. Ta gpi DTFT
la pho phuc (complex spectrum) hay ngan gpn
la
pho cua tin hieu roi rac x[n]. Tir day ta
thay can thiat phai xay dung bien doi Fourier roi rac cho truong hgp day x(n) hiru ban.
b. Bien ddi Fourier cua tin hieu rai rgc DFT
Truong hgp x(n) hiru ban, chieu dai N (0 < n <
N-1)
Ikjt
Dat
Q =
(k
6
Z) ta co bien doi Fourier roi rac cua x(n):
n
X(k)=X

x(n).e^^"
(2;
Hay
X(k)
= 2 x(n)(cos(-^kn) -
i
sin(-^kn))
(3;
- Lugng phep tinh: DFT phai thuc hien
N^
phep nhan phuc va
N(N-I)
phep cong phuc
Suy ra so phep tinh cong va nhan so thuc:
+
2N^
phep tinh lugng giac
+
4N^
phep nhan so thuc
+ N (4N-I) phep cong so thuc
+ Mot so phep toan chi so va dia chi
da
nap x(n)
10
Nhugc diem: thai gian tinh toan
se qua dai va
dung lugng
nha cua
thiet

bi se
phai
Ion.
c. Bien doi Fourier nhanh FFT
Truong hgp N=2'
TV
Ta chia day x(n) thanh
2 day co
chiau dai
—:
-
Day
g(n) gom
cac gia tri
chan: g(r)
=
x(2r)
N
- Day h(n) gom
cac
gia
tri
le:
h(r)
=
x(2rHl)
trong
do r:
0,
1

Taco:
X(k)N=
Y.
XW-WH'"
(W^^e^)
-^
X(2V)KM^'''^Y.
x(2r+l)^.WN
(2r+l)k
r=0
= X
g(r)^.W^^^
+
^
h(T)K.WK'\w^'
r-0
2
= X
g(r)^.W^*
+WN'.X
h(r)i.W^*
r=0
G(k)
+
WN"
.H(k)
( vai k:
0,
A^
-1)

eCO)
-
xtP3
CCU-XC25
eC2) -
KC4)
eC3)
-
xC6)
CDFT)-
0(0)
0(1)
\
G(2)
\^ \^
Gt3) \^ \^^
y^.
/" /^
/\ •^ /W2
JK
JXT
/^W3
xco>.
X(2>
XC3)
KO) = xa)
hCD^'tpS
K2)
-
xp3

K3:
-
JtC?:
fDFT)-
H(0)
H(l)
H(2)
H(3)
//x\-^
// \"
/
>.
V/4
V
V75
V "we
W7
XC5)
XC6)
XC7)
(4)
(5)
(6)
(7)
(8)
Hinh 6 Sa do FFT-8 diem chia
2
11
Ta
CO thi tilp

tuc phan chia moi day g(n) va h(n) thanh 2 day con de giam dp phuc tap
cua
DFT
g(0) = K(0)
gC2) = i(4)
(DFT)2
A(0)
A(l)\
\ 'll
G(0)
G(n
\
/w.
my
g(l)
=
x(2)
S(3)
= x(6)
(DFT)2
BM/"
m
/
\
A^
/\W4
W6
G(2) \ \
0(3) \ \
>/

/ /W2
X A
/ ^^
XC3)
h(0) = x(l)
li(2)
=
xP)
W.
HCO)
H(l)
W5
Kl) = xC3)
3iC3)=xC7)
(DFT)2
IXO)
/
D(l)
,
\
A^^
Aw?
W6
H(2)
/ /
HC3) /
\
W6
W
X(4)

XC5)
X(6)
Hinh 7 FFT 8
diem
Cuoi cimg dua ve tinh DFT dcm gian nhat, DFT 2 diem:
a(0) =
g(0)=x(0)
a(l)
=
g(2)
=
x(4)
A(0),
A(l):
W-
FFT 2 diam:
Hinh 8 FFT 2 diem
A(0) = a(0) +
a(l)WN'
A(l)
= a(0)+a(l)WN
Hieu qua tinh toan: so phep tinh chi con
N.log2N
So sanh hieu qua tinh toan:
12
Bang
1:
So
sanh do phirc tap cua
2

thuat toan
DFT
vd FFT
Dp
dai
N
4
8
16
32
64
128
256
512
1024
So phep tinh
DFT
156
632
2544
10208
40896
163712
655104
2620928
12327936
FFT
8
24
64

160
384
895
2048
4608
10240
Chit v: Hien tugng ro pho (leakage) xay ra trong mien tan so. Ro pho la hien tugng pho cua
tin hieu bi do vao 1
loat
cac tan so xung quanh tan so cua tin hieu. Nguyen nhan la do su cat
ngan tin hieu. Khi do tin hieu x(n) khong tuan hoan,
tran mian
tan so se thu dugc khoang
tan so rpng trong pho FFT.
De giam hien tugng ro pho ta dimg
1
ham cira so nhan voi tin hieu vao de tro thanh tin
hieu tuan hoan. Khi do
bian
dp moi tan so ly tuong se dugc nam bat chinh xac, khong co ro
pho.
Lua chon ham cua so:
Tiiy
vao ung dung ta chpn loai cira so se dimg. Dang ham cira so anh
huong rat
Ion
den dp chinh xac cua viec xap xi ham tan so. Viec chpn ham cira so nao de
xap xi hoa ham tan so, khong chi phu thupc vao dp chinh xac yeu cau, ma con phu thupc
vao ban che ve thai gian tinh toan, vi ham cira so cho dp chinh xac cang cao thi viec tinh
toan se cang phirc tap, va thai gian tinh se cang

Ion.
Do do viec chpn ham cira so phu thupc
vao su toi uu giiia dp chinh xac
yau
cau va thoi gian tinh.
13
Cira so
Barlett
Blackman
Harming
Hamming
Kaiser-
Bessel
Non (boxcar)
Tukey
Welch
Bang 2:
Kiau tin hieu tot
nhat
Batky
Bat ky hoac tin
hieu phuc tap
Bdtky
Bitky
Batky
Tin hieu ngan va
lay mau dong bp
Batky
Bitky
3dng ddnh gia mot so cira so

Dp phan giai tan
A
so
Tot
Kem
Tot
T6t
Khong tot
Tot nhat
T5t
T4.
Ropho
Khong tot
Tot nhat
T6t
Khong tot
T6t
Kem
Kem
T6t
Dp chinh xac
Khong tot
Tot
Khong tot
Khong tot
Tot
Kem
Kem
Khong tot
d. Mot so ket qua md phong

Chuong trinh
1
Chuong trinh nay nham minh hoa
im
diem cua viec diing cua so
(o
day la cira so Harming)
khac phuc hien tugng ro pho. Code dugc trmh bay trong phu luc
7.1.
Kat
qua dugc tha hien trong hinh duoi day:
Hinh
9
Phan tich FFT
khi
diing vd khong diing cica
so:
so
sanh ropho
14
Chvrang trinh
2
Tuy bi nhugc
diam la
bi ro pho nhung khi(kh6ng)dung cira so thi dp phan giai pho lai tot
hon. Trong chuong trinh nay thi tin hieu can phan tich la tong hgp cua hai tin hieu hinh sin
350 va 352 Hz, dugc
lay
mau a
xkn

so
1000
Hz trong thoi gian 0.8 giay (nhiau ban chuong
trinh 1). Code dugc trmh bay trong phu luc 7.1.
Kat
qua thu dugc nhu hinh duoi cho thay
khi khong sir dung cua so thi viec tach 2 tin hieu hinh sin lai hieu qua hon (dp phan giai tot
hon).
0
220 24D 260
280
300
320
340 360 380 400
Hinh 10
Phan tich FFT khi dung vd khong dung
cica
so: so sanh do phan gidi
Chuong
trinh 3
Tuong tu nhu chuong trinh 2 nhung a day tin hieu bi cong them nhieu
tr4ng.
Code dugc
trinh bay trong phu luc 7.1. Tin hieu trpn nhieu dugc mo ta trong hinh duoi day, thay ro
rang tin hieu chiu anh huong boi nhiau nang
na.
0 0.02 0.04
0 06
0.08 0.1
0 12 0 14 0 16

OK
hai tin hieu hinh sin + nhieu
Hinh II
Tin hieu chim trong nhieu
Ket qua phan tich pho cho
th^y
van co
thi
nhan
hik
cac thanh
phAn tin s6
khi dimg bien
doi
Fourier:
10
10
10
10
khong cua so
hanning
J
L
300 310 320 330 340 350 360 370 380 390 400
Hz
Hinh 12 Phan tich FFT khi dung vd khong dung cua
so:
tin hieu tron
nhieu
6.3.2 Phan

citng
he thong
So do tong quan
MMA7260Q
DSPIC30f4013
Chuung
trinh
canh
bao
Cong
COM
COMPUTER
Hinh 13 Sado tong quan
16
Cac linh kien
Cam bien gia too MMA7260Q vd mach dieu khien
La loai cam bien gia
toe
dugc cha tao
tran
cong nghe vi ca dien tu.
+ Dua ra thong so tren 3
true
tpa dp X, Y, Z.
+ Gia thanh re de thiet ke mach dieu khien
Bao gom :
+
G-Cell
Sensor : chuyen gia toe -> gia tri dien dung
+

Oscillator : bp tao dao dpng
+ Clock Generator : tao xung
+ C to V converter : chuyen gia tri dien dung -> dien ap
+ Gain, Filter : khuach dai va
Ipc
+ X, Y, Z temp comp : gia tri tam
+ Control logic EEPROM trim circuits
g-Sefectl
9-Seiect2o-
ra
Sleep Moce(
G-C«il
Sersor
Osolabr
Cttc<
Generator
CtoV
Corvrter
Gair
RSer —r
X-Terrp
Comp
Control
Lege
EEPROM
TrFT Cira)ts
Y-TfifTD
Corrp
Z-Teirp
Corrp

Vss
Hinh I4Sadokh6iMMA7260Q
Nguyan
ly
va tinh nang dac biet
Nguyan ly:
+ Khoi
G-Cell
trong cam
bian
co cau
true
2 tu back-to-baek.
+ Khi gia toe thay doi -> gia tri dien dung thay
doi:
C=AE/D
Tinh nang dac biet:
+ Cho phep chpn
lira
4 che dp nhay
17
•OYj,,.
-OZ-
DAI HOC
QUOC GIA
HA
NQI
B>iGJAM
THONG
TIN rna VIEN

omccC'C0 9z
Bang 3: Cdc che do nhay
g-SeIect2
0
0
1
1
g-Selectl
0
1
0
1
g-Range
l-5g
2g
4g
6g
Sensitivity
800mV/g
600mV/g
300mV/g
200mV/g
+ Che dp nghi cho Sleep Mode de tiet kiem nang lugng boat dpng o muc tich cue thap.
Khi
b cha
dp nay dong tieu thu se giam ve muc 3uA
+ Co cac bp
Ipc ban
trong
+ He so tuyan tinh

Mot so img dung cua cam
bian
gia toe MMA7260Q:
+ Do va diau khian muc rung
+ Dinh huong 3D trong khong gian
+ Phat hien va cham, nhimg thong tin ve gia toe, van toe va dp dich chuyen giup phan
bi^t
viec va cham va khong xay ra va cham.
+ Dieu khien du doan kha nang lam viec cua may moc thiat
bj
+ Dpc mot so thong so sinh hpc trong co tha nguoi.
Vi
dieu khiin DSPIC30F4013
+ Khoang dien ap rpng 2.5 -> 5.5V
+ Bp chuyen doi A/D 12 bit, 13 kenh
loi
vao,
luon sin
sang trong ca che dp Sleep va
Idle
+ Bp nho Flash
Ion
48Kbytes,
2Kbytes RAM,
1
Kbytes EEPROM khong bay hoi
+ CPU
CO
cau
true

RISC thay cho
kian
true Harvard
+ It tieu ton dien nang, khoang nhiet rpng
+ Kha nang lap trinh
Ghep noi may tinh bang cong COM
(xem
phu luc
7.2)
+
Truyan du lieu noi tiap khong dong bp
+ Toe dp truyan nhan
cue
dai la
10Kbps
Sa do
nguyen ly
r L
.
•*•
I 1 ii 1 I i i I I I
,
1 I
,
///«/;
75
C(iw ^/e«
g/'o
foe
MMA7260Q vd bo mach dieu khien

OSCIJCLKIH
OSC2/:XlKJ/RC15
IKTO/RAU
EUUC2XX;lKD0
EMUD2KX:2<HD1
OC3«D2
OC4/RD3
lCiyiNTlfla>8
1C2/INT2JRD9
'LJ-
32.768k
AN2JSS1/L VDIH*CH*fl?B2
AK3JCH5/RB3
AH4flC7*c:K6/RB4
AH5nC8*CN7/KB5
PGC«MUC/AN6JOCrA»RB6
PGD/EMUD/AN7/RB7
AN8/RBS
AH9>CSCKJRB9
AHIO^CSDI/RBIO
ANlljCSEXi/RBll
AHI2JCOFS/RB12
CRXl/RTO
CTXl/RTl
D1
RX/SDIlADAJRf::
EMUD3/D1 TX>SDO 1 /SCL/RTS
U2RX;CH17/Rr4
U2TXJCM18/Rr3
EMUC3*SCK1/Rr6

EMTID1 JSOSClJT2CICai IATXKN1/EC 13
EMTICI JSOSCXiJTl CK/D1ARXJCKOJRC14
DSPIC3DF4013
13 ADCl
20 ADC2
21
AE>C3
22
TEMPQUT
23 DATA RED
24
DATA_GR£EM
25 PGC
E
26
bCD RW
27
RS
15 D4
14
DS
11 D6
ID D7
_5 BUT^CLICJiOW
_4 ^CLKJtOW
1 SPA
BTl
BT2
44
SCL

3^
Aux_Rx
2
Aux_T
43
LCpB*ckLieht
Hinh 16 Vi
dieu khien
DSPIC30/4013
19
<
—4
.1
I—
k
ti
EJ'-
fT3'
^
T
L
—
3
;*^»
dt;
T
t»
=^1
//?«/? 17 Sado
nguyen ly

Viec can chuan cam bien dugc trinh bay trong phan phu luc
ciia
bao cao nay.
6*3.3
Cdc ket qua thuc nghiem
Mo ta: tin hieu rung dugc cam bien thu nhan va chuyan thanh tin hieu dien
6
loi ra, roi
dugc dua vao vi
diau
khian qua ADC, qua day thu dugc tin hieu roi rac thai gian theo 3
chieu.
=>
truyen noi tiap qua cong COM. Cong viec cuoi cimg la cua may tinh, nhan dir
li^u
va tinh pho SFFT.
Mo ta chuong trinh:
20
Giam sat rung
Kich
thich nhan tao hoac
do moi
trirong
xung quanh
then
gian
Tinh \
^^^^^ ^P ^^•
- tan so
toan

Hinh
18 Chuong trinh gidm sat
So do thuat toan:
Nhan du
lieu
3 kenh
Tinh pho FFT
Hien thj
pho
Tinh
Fmax
Hinh 19Sado thuat todn
Tao tin hieu rung boi mot bp tao rung voi tan so rung dugc
diau
chinh boi may phat xung.
Gin
cam bien gia toe
lan
bp tao rung. Thu dugc mot so ket qua sau:
21
Hinh
20 Bdn mach vi dieu khien
Hinh
21 Bdn mach cam bien gia
toe
22
B^£M:i:.'
Y
•-
-'All V

•^j'-;.
1
^^'<^
1
-
.,4
jH^^-
^^Ki
•
<^-<'.^>4-i,-a.^
rss^^^;-
^
* •'* \
•
Hinh
22
BQ
tao rung
•• ^,.;>
i
;•
II
^1
^^"^
r-^^
I
vd
•i%:./:
1
y^"

r
f
6fl« W4)fc/i caw
fe/e«
^^^
Sf'-^^
"'^'
y^
f
^^^N^
IM^^H
1
• ,.,*.
"•^"''"
^-^
,^^ •'
^
Hinh
23 He thong do rung
23
;i£888S3*':^^3^«^'
i'-^^
•'C
Hmh
24
May
phat xung (f=29.5 74Hz)
Hmh 25 Ket
qua
chuong trinh phan tich

pho,
F
=29.9
Hz
24
Hinh 26 May phdt xungf=31.218Hz
Hinh
2
7
Ket
qua chuong trinh phan tich
pho,
F =
32.3Hz
25
•3-»-'W'-,
Nhan xet:
kit
qua phan tich pho thai gian thuc cua chuong trinh co dp chinh xac tot
(kho^g
3% gia tri do) cho thay kha nang ap dung tot cua chuong trinh cho cac thuat toan
giam sat cong trinh sau nay. Su sai khac 3% co tha dugc giai thich do dp chinh xac cua may
phat song hinh sm, do dp phan giai cua chuong trinh tinh FFT-256, va co the khac phuc
nho cau hinh phan cung tot hon
nixa.
Cac ket qua trong hinh 25, 27 thuc chat la ket qua tinh pho tin hieu tai 1 thai diem xac dinh
FFT-256 diem. Ngoai ra chuong trinh con co tha hien thi tin hieu rung theo thai gian. Tuy
nhien
viae
lam dung do hoa may tinh se gay nen hao phi tai nguyan (khi di vao thuc

ta
thi
vi^c
hien thi pho theo do hoa nhu hinh 25, 27 la khong can thiet ma chi can cac
kat
qua luu
tni dugc).
Hinh 28 la ket qua thu tren kenh thang dung -
true
Z (dugc phong to trong 1 khoang thai
gian ngan de thay dang hinh sin) trong suot thoi gian thir nghiem (hon 30 giay) va hinh 29
la ket qua phan tich pho, cho chinh xac tin so rung la Hz.
Da
thay rang voi tap du lieu rat
nhieu (6544 mau) thi dang pho thu dugc la cue ki ro net,
diau
nay
phii
hgp cac cac ly thuyat
xtr
li tin hieu. Ve ban chat each tinh FFT trong hinh 25, 27 la SFFT (Short FFT) mot thao
tac
CO
y nghia han nhieu voi FFT binh thuong vi co tha mo ta su thay doi ve pho theo timg
thai diem.
2300
0.5 1
thoi gian (s)
Hinh
28 Quan sat tin hieu theo thai gian tren kenh Z

26