madrid measurement apparatus to distinguish rotational and irrotational displacement
DESCRIPTION
MADRID Measurement Apparatus to Distinguish Rotational and Irrotational Displacement. Rafael Ortiz Graduate student Universidad de Valladolid (Spain). MADRID. Problem to solve Reasons of choosing this option Description of the device First result Conclusion. Introduction. - PowerPoint PPT PresentationTRANSCRIPT
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MADRIDMeasurement Apparatus to Distinguish Rotational and Irrotational Displacement
Rafael OrtizGraduate student
Universidad de Valladolid (Spain)
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MADRID
Problem to solve Reasons of choosing this option Description of the device First result Conclusion
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Introduction
High accuracy in microsurgery• Vitreoretinal microsurgery MICRON• Neurosurgery LASER MICRON
Involuntary movement of the hand hinder the desired accuracy.
Tremor Jerk Drift
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Vitreoretinal microsurgery
Five degree of freedom Two rotation Three translation
Tip tracking
↓↓↓
ASAP
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Vitreoretinal microsurgery
Four degree of freedom Two rotation Two translation
Laser tracking
↓↓↓
6
Options to solve the problem
Gyros.
CCD camera
MADRID
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Use a par of gyros
Translation information is missing
Device should be useful for laser micron calibration.
Impossible to set a gyros above a laser ray
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CCD camera
High speed ( 100 fps ) High accuracy ↔ High resolution Very expensive system
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MADRID
First idea: Only two dots are required to draw a line. If the laser is tracking in two different positions , the
angle may be calculated
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21arctan
AA
BB
A1 A2
B1
B2
Point 1
Point 2
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3D problem
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Configuration
Position SensingDetector #1
Position SensingDetector #2
DATAoutput
PowerInverse Bias
Band pass Optical filter
Standard Cube Beam splitter
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Bandpass optical filter
Benefit: eliminate most of the ambient light
Type: 10LF20-670 C. Wavelength:
667.3nm FWHM: 19.4nm P. Transmission:
53.1%
10LF20-670, Newport, Irvine, CA
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Laser Diode
Focusable Laser Features:
CWWavelengths670nm ±10nm,
DiameterLDM, Circular: 5mm;
Focus Range LDM, Circular: 150mm to Infinity;
NT38-920,Edmund optics, Barrington, NJ
0.5m 1m 2m 5m
<0.5 <0.5 <1 1
Spot Size (mm) at DistanceSpot Size (mm) at Distance
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Standard Cube Beamsplitter
BS CUBE STANDARD 12.5MM TS
Size: 12.5mm x 12.5mm Reflection : 50 % Transmission : 50 %
NT45-111, Edmund optics, Barrington, NJ
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Position Sensing Detector
1 cm2 square PSD & associated amplifier circuit.
Voltage analogd of the X,Y and spot intensity
Reverse Bias is applied
DL 100- 7PCBA ,Pacific Silicon Sensor Inc. ,Westlake Village, CA
Sum(y)Ch7V(y)Ch6
Sum(x)Ch5V(x)Ch4PSD #2
Sum(y)Ch3V(y)Ch2
Sum(x)Ch1V(x)Ch0PSD #1
FormulaMeaningChannel
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11 ChChAx
32
11 ChChBy
54
22 ChChAx
76
22 ChChBy
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Calculation of two angles
da
xxArc 21tan
da
yyArc 21tan
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Calculation of displacement
tan1 cbaxg x
tan1 cbayg y
tan2 cbdxg x
tan2 cbdyg y
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General Scheme
Ch6Ch5Ch4
Ch3Ch2Ch1Ch0
FilterBand pass
Cutoff 22Hz
Y1
X2
Y2
Transform volts into microns
Laser
Ambient light
Band pass Opt filter
Laser
Beam splitter
Ch7
ADcard
PSD#1
PSD#2
Subtract Offset
Transform microns into angles and
positions
X1
Alpha Beta
Gx Gy
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First Result
Different modes Only translation Only angle Angle and translation
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Only translation
Redundant data (alpha and beta must be null) Two studies
Full Range (step 0.04 inch or 1mm) Small step (step 2 mil or 50 micron)
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Full Range (only translation)
-2500 -2000 -1500 -1000 -500 0 500 1000 1500 2000 2500-2500
-2000
-1500
-1000
-500
0
500
1000
1500
2000
2500Final PSD1 & PSD2 in micron
Xaxis(micron)
Yax
is(m
icro
n)
8.7268
6.4684
-0.0058
-0.0058
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Small Step
6.7942
4.0104
-8.8044
-2.1234
-600 -500 -400 -300 -200 -100 0 100 200 300 400 500 600-600
-500
-400
-300
-200
-100
0
100
200
300
400
500
600
X axis(microns)
Y a
xis(
mic
rons
)
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Only angles
Wheel to reach different orientation
of angle ALPHA
Wheel to reach different orientation
of angle BETA
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Angle (Alpha)
0 5 10 15 20 25 30 35 40 45-1.5
-1
-0.5
0
0.5
1
1.5
Set of data
Alp
ha(D
egre
es)
Real measurment of angleReading with MADADError
Error
Range =2.5653°
Maximum Error 0.0268 °
Linearity =1.04%
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Angle (Beta)
0 5 10 15 20 25-1.5
-1
-0.5
0
0.5
1
Set of data
Bet
a(D
egre
es)
Real measurement of angleReading with MADADError
Range =2.2526°
Maximum Error 0.0517°
Linearity =2.29%
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Angle in completed mode
0 500 1000 1500 2000 2500 3000 3500 4000 4500-0.035
-0.03
-0.025
-0.02
time(millisecond)
Rot
atio
n A
lpha
(deg
ree)
0 500 1000 1500 2000 2500 3000 3500 4000 45000.41
0.415
0.42
0.425
0.43
time(millisecond)
Rot
atio
n B
eta(
degr
ee)
Standard derivation of error
in alphaStd alpha
0.0022° ≈ 8’’
Standard derivation of error
in betaStd alpha
0.0022° ≈ 8’’
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Translation in completed mode
0 500 1000 1500 2000 2500 3000 3500 4000 45001135
1140
1145
1150
1155
1160
1165
time(millisecond)
Pos
ition
Gx
(mic
ron)
0 500 1000 1500 2000 2500 3000 3500 4000 4500125
130
135
140
145
150
time(millisecond)
Pos
ition
Gy(
mic
ron)
Standard derivation of error
in x translationStd Gx error
4.1876 micron
Standard derivation of error
in alphaStd Gy error
4.0152 micron
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Real tremor (Rotation)
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000-2.5
-2
-1.5
-1
time (millisecond)
rota
tion
alph
a (d
egre
e)
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000-4.6
-4.4
-4.2
-4
-3.8
time (millisecond)
rota
tion
beta
(de
gree
)
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Real tremor (translation)
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 100004000
4500
5000
5500
6000
6500
7000
time(millisecond)
tran
slat
ion
gx (
mic
ron)
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 100007500
8000
8500
9000
9500
10000
10500
time (millisecond)
tran
slat
ion
gy (
mic
ron)
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Conclusion