Sensor-Deployment Strategies for
Indoor Robot Navigation
Aaron Chun-Han Lin 林均翰
Research Center for Information Technology Innovation Academia Sinica
Tel: 886-2-2787-2335 Fax: 886-2-2787-2372
Email: [email protected]
Previous Project
2011/8/11 2
ITRI project
Demo video
Sensor-Deployment Strategies for
Indoor Robot Navigation
Sensor
2011/8/11 3
Detection
Display
Embedded system
15-20%
cost
Market prediction of MEMS sensor on cellular phone
Wireless Sensor Network (WSN)
2011/8/11 4
Crossbow Mica2
Sense: light, motion, temperature, magnetic fields, gravity, humidity,
vibration, pressure, electrical fields, sound, ...
Project Testbed
2011/8/11 5
http://fiji.eecs.harvard.edu
/Volcano
http://db.csail.mit.edu/
http://www2.ece.ohio-state.edu/~ekici/
Harvard moteLab
COMMON Sense project
http://www.csail.mit.edu/
Importance of Deployment Technique
2011/8/11 6
Coverage
Detection ratio
Connectivity
Fault tolerance
…
Lifetime
Energy
Maintenance
Deployment cost
Design of Deployment Technique
2011/8/11 7
Various WSN systems
Different requirements
Developing 3 techniques
Indoor robot navigation
Debris-flow observation
Environment surveillance
Robot
2011/8/11 8
Routine service
2011/8/11 9
Space navigation
Security
Housekeeping
Delivery
Medical
…
http://www.worldrobotics.org/
Indoor Robot
2011/8/11 10
Localization
Positioning sensor
A set of sensors can
provide localization
service
Wireless
Infrastructure
Coverage
Robot Navigation
Challenge
2011/8/11 11
Traditional deployment
Full coverage
Tradeoff
Cost Coverage
How
Reducing sensor
Where
Keeping coverage
Acceptable error
Positioning sensor
Error Model
2011/8/11 12
Target model
x’ = x + d cos(q+r)
y’ = y + d sin(q+r)
q ’=(q+r) mod 2p
Actual configuration P(f)
Configuration error
err(f)=max(P(f) – f)
|err(f)|
=|max(P(f) – f)|
=(max((P(x) – x)2 +
(P(y) – y)2))1/2 Positioning sensor
Minimum Deployment-Set Problem
2011/8/11 13
MDS (G, Errmax)
Width of hallway
Width of track
…
The minimum
deployment-set problem is
NP-hard
Vertex cover problem
Deployment Procedure
2011/8/11 14
Map
Track
Deployment strategy
Initial Construction
2011/8/11 15
Divide graph
Estimate error
Compute number
Complexity Probability
Decide location
I-EVEN
I-MAX
1
2 1 3
Even
1
2 1 3
Max
Refinement
2011/8/11 16
Combine sub-graph
Confinement region
Circular route
Tree-based
Breadth-first
Utility-based
Performance Evaluation
2011/8/11 17
ITRI
Cricket
Size of Deployment Set
2011/8/11 18
Refinement ratio
Improvement ratio
Configuration Error
2011/8/11 19
Average Variance
Conclusion
2011/8/11 20
Sensor-deployment strategies for indoor robot navigation
Technique: sensor network
Problem: indoor robot navigation
Problem complexity
Deployment strategy
Performance