Mobile robot using different senses Motivation Senses for Robots - - PowerPoint PPT Presentation

University of Tübingen Institute of Physical Chemistry 1

Mobile robot using different senses

ISOEN 2002

• M. Wandel*, A. Lilienthal+, A. Zell+, U. Weimar*

*ipc, AG Weimar www.ipc.uni-tuebingen.de/weimar/

+WSI-RA, AG Zell

www-ra.informatik.uni-tuebingen.de

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Overview

• Motivation

State of the art

• Experimental set-up

Mobile robot Sensor system

• Experiments

1-Dimensional experiments in a corridor 2-Dimensional experiments in large room

• Findings
• Conclusions
• Outlook

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Senses for Robots

Sight (Cameras) Hearing (Microphones) Touch (Tactile sensors) Smell (Gas sensor system) Taste (Electronic tongue)

Extending the possibilities

Electronic Watchman can oversee chemical stocks and detect leakages

Motivation

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Biomimetic

• Path Finder
• Virtual Umbilical
• Repellent Marker

Potential Applications

• Trail following

Trail defined life time

• Marking

Mark of Cleaned Floor

• Source Detection

Direction finding

Rotating Robot Short Distance (Duckett et al.) Three dimensional Odour Compass

– Defined air stream (Nakamoto et al.)

Detection of odour plumes

Plume tracking (Russel et al.)

– Defined air stream needed

Robots with Gas Sensors: Applications

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Biomimetic

• Path Finder
• Virtual Umbilical
• Repellent Marker

Potential Applications

• Trail following

Trail defined life time

• Marking

Mark of Cleaned Floor

• Source Detection

Direction finding

Rotating Robot Short Distance (Duckett et al.) Three dimensional Odour Compass

– Defined air stream (Nakamoto et al.)

Detection of odour plumes

Plume tracking (Russel et al.)

– Defined air stream needed

Source Detection

• Direction finding

Rotating Robot Short Distance (Duckett et al.) Three dimensional Odour Compass

Defined air stream (Nakamoto et al.)

• Detection of odour plumes

Plume tracking (Russel et al.)

Defined air stream needed

• Convection / Diffusion profile

Map Building

No Defined Airstream needed

Robots with Gas Sensors: Applications

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Experimental: Mobile Robot “Arthur”

Mobile Robot “ATRV-Jr”

• Skid Steering
• Standard PC inside
• Ultrasonic sensors
• Wireless Ethernet

Additional Sensors

• Laser range finder
• Stereoscopic camera

System

• Gas sensor system

mounted inside the robot, behind front window 60cm

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Experimental: Sensor System

VOCmeter Vario

• Commercially available
• Lightweight, small
• Low power consumption

(24V DC supply possible)

• RS-232 interface
• Various sensors types

available (MOX, QMB, U/I)

• Up to 8 sensors, connected

with thin flexible cables

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1-Dimensional Location

Locations

No ventilation! No personnel traffic

Experiments

• Analyte used: Ethanol
• Recordings
• dometry, sensor system, laser range finder,
• temperature, humidity (offline)

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500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500

• 20
• 15
• 10
• 5

s [m]

t [s]

2 4 6 8 10 12 14

∆n [ppm]

Results: 1-Dimensional Location

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500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500

• 20
• 15
• 10
• 5

s [m]

t [s]

2 4 6 8 10 12 14

∆n [ppm]

Results: 1-Dimensional Location

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500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500

• 20
• 15
• 10
• 5

s [m]

t [s]

2 4 6 8 10 12 14

∆n [ppm]

Results: 1-Dimensional Location

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Determination of Source Position

1 2 3 4 3000 3100 3200 3300

• 10
• 5

5 10

s [m]

t [s] ∆c [ppm] 2500 2750 3000 3250 3500

• 20
• 15
• 10
• 5

s [m]

t [s] 2 4 6 8 10 12 14 ∆c [ppm]

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2-Dimensional Location

• Unventilated
• One side of the room is a window front
• The automatic source was placed in the middle of

the room

• The robot’s path describes a rectangular helix

x y

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Results 2-Dimensional Location

2 4 6 8 10 12 1 2 3 4 5

signal [a.u.] University of Tübingen Institute of Physical Chemistry 15

Comparison Summer - Winter

2 4 6 8 10 12 1 2 3 4 5 s i g n a l [ a . u . ] 2 4 6 8 10 12 1 2 3 4 5 signal [a.u.]

Summer Winter

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Peaks / Position

2 4 6 8 10 12 1,0 1,5 2,0 2,5 3,0 3,5 4,0

Summer Winter

Y [m] X [m]

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Time of Occurrence

1000 2000 3000 4000

Signal (baseline) Signal (peak) Online computed baseline

topen, predicted topen, real

Offline fit time / s

signal / a.u. 1000 2000 3000 4000 t [s]

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Findings

• Signal nearly independent of stick position
• Simple mounting of the sensor, without fan,

without pumping unit, sufficient

• Meaningful measurements only during movement
• Even small leaks can be detected

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Conclusion

• In a 1-dimensional environment the position
• f the source can be estimated within a range
• f 1m
• In 1- and 2-dimensional environment the

time of occurrence of the leak can be computed with good precision

• The measured concentration profile requires

time consuming search strategies e.g. map building, this is possible because of the stable concentration profile

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Outlook

• Implementation of a feedback from the

sensor signal evaluation to the driving programme

• Larger rooms
• Classification of the analyte

Using a sensor system with different sensors including QMBs and pattern recognition software

• Testing in real world environment

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Acknowledgements

Landesforschungsschwerpunktsprojekt Baden-Württemberg Sensing organs for mobile robots Project partners:

• Wilhelm-Schickard-Institut für Informatik, AG Zell (coordinator)
• Zoologisches Institut, AG Schnitzler
• Institut für Physikalische und Theoretische Chemie, AG Weimar

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Thank You