Where am I? Sensors and Methods for Mobile Robot Positioning

196 Part II Systems and Methods for Mobile Robot Positioning
Start
point
A
Desk
with
chairs
B C D
Closed door
Arbitrary
target point
E
Figure 8.12: Actual office environment and robot's trajectory during the
exploratory travel phase. (Courtesy of [Bauer and Rencken, 1995]).
A
Landmarks caused
by specular reflections
B C D
E
Figure 8.13: Gathered features and robot's return trajectory (Courtesy of [Bauer
and Rencken, 1995]).
sured by hand at control points A through E,
the results are listed in Table 8.2.
When the robot was programmed to return
to its starting position, the resulting path
looked much smoother. This is because of the
many features that were stored during the
outbound trip.
Table 8.2: Hand-measured position error of the robot
at intermediate way-points during the exploration
phase (Adapted from [Bauer and Rencken, 1995]).
Point
Absolute x,ycoordinates
[cm]
Pos. Error
[cm] (in)
Orient.
Error [°]
A (0,0) 2.3 (7/8) 0.7
B (150, -500) 5.7 (2-1/4) 1.9
C (1000, -500) 9.1 (3-1/2) 5.3
D (1800,-500) 55.8 (22) 5.9
E (1800,-800) 63.2 (25) 6.8