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robots:armadillo:calibration:welcome

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Armadillo Calibration

Odometri constants

It is assumed that the turningpoint for the belts is the center of the belts.

cl = 0.00348377
cr = 0.003193242
w = 1.68336

UMB-mark test

UMB (168 KB)
Measurement and Correction of Systematic, Odometry Errors in Mobile Robots. Download Paper 58 (803 KB)
Correction of Systematic Odometry Errors in Mobile Robots. Download Paper 59 (177 KB)
Where am I? Sensors and Methods for Mobile Robot Positioning. Download book from University of Michigan (12.2 MB)

BEFORE CALIBRATION

$r_{c.g.,cw}=\sqrt{(X_{c.g.,cw})^2+(Y_{c.g.,cw})^2}$

$r_{c.g.cw} = 83.43 cm $
$r_{c.g.ccw} = 128.67 cm$
$L = 2 m $

CLOCKWISE, cw
ϵx [cm] ϵy [cm]
1 -63 -63.5
2 -50.5 -59
3 -34 -65
4 -26.5 -78.5
5 -41 -91.5
Xc.g.=-43Yc.g.=-71.5

COUNTERCLOCKWISE, ccw
ϵx [cm] ϵy [cm]
1 -71 97
2 -100 112
3 -74 87
4 -69 123
5 -65.5 100.5
Xc.g.=-75.9Yc.g.=103.9

Calculations

$$\alpha = \frac{x_{c.g.,cw}+x_{c.g.,ccw}}{-4L}\cdot \frac{(180^{\circ})}{\pi}$$

α = 851.99 cm
8.5199 m

$$ \beta = \frac{x_{c.g.,cw}-x_{c.g.,ccw}}{-4L}\cdot \frac{(180^{\circ})}{\pi} $$

β = -235.7484 cm
-2.357 m

$$R = \frac{L/2}{sin(\beta /2)} $$

R = -48.7 m

$$E_d = \frac{D_R}{D_L} = \frac{R+b/2}{R-b/2} $$

b = 1.524 m
$E_d$ =0.969

$$b_{actual} = \frac{90^{\circ}}{90^{\circ}-\alpha}\cdot b_{nominal} $$

$b_{actual}$ =1.6834calibrated value of wheelbase
1.524before calibration

$$c_l = \frac{2}{E_d+1} $$

$$c_r = \frac{2}{(1/E_d)+1} $$

Correction factor Before CalibrationAfter Calibration
$c_l$ =1.0156 0.003430.003484
$c_r$ =0.9844 0.00324 0.003193

AFTER CALCULATION

$r_{c.g.,cw}=\sqrt{(X_{c.g.,cw})^2+(Y_{c.g.,cw})^2}$

$r_{c.g.cw} = 4.12 cm$
$r_{c.g.ccw} = 29.35 cm$

CLOCKWISE, cw
ϵx [cm] ϵy [cm]
1 -6 -14.5
2 -12.5 -10
3 5.5 8
4 -5.5 -7
5 2.5 10.5
Xc.g.= -3.2 Yc.g.= -2.6

COUNTERCLOCKWISE, ccw
ϵx [cm] ϵy [cm]
1 -38.5 24
2 -27 10
3 -19.5 11
4 -22.5 20
5 -22 4
Xc.g.=-25.9Yc.g.=13.8

robots/armadillo/calibration/welcome.1351071443.txt.gz · Last modified: 2021/08/14 04:19 (external edit)