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2
Motivation
- Goal : Positioning the robot with respect to the
absolute sound energy Aly Magassouba, Nancy Bertin and Francois - - PowerPoint PPT Presentation
absolute sound energy Aly Magassouba, Nancy Bertin and Francois - - PowerPoint PPT Presentation
Audio-based robot control from inter-channel level difference and absolute sound energy Aly Magassouba, Nancy Bertin and Francois Chaumette IROS 2016 Presented by Youngki Kwon Motivation Goal : Positioning the robot with respect to the
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SLIDE 3
3
Motivation
- Goal : Positioning the robot with respect to the
sound source at given distance and orientation.
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Motivation
- Goal : Positioning the robot with respect to the
sound source at given distance and orientation.
How? Audio-based robot control
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5
Audio-based robot control
- Real-time robot control to use sound!
- Aural Servo
- Techniques which uses feedback information
extracted from a aural sensor to control the motion of a robot
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Geometric configuration
- Consider that the sound source
is in front side of the robot
- ππ‘: omnidirectional sound source
- π1, π2: microphones
- π: midpoints of microphones
- π: center of robot
- αΆ
π (π£, π₯): control input (2-DOF)
- π£: velocity along π§π
- π₯: angular velocity around π¨π
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General framework
- The aim is to minimize an error π π’
π π’ = π‘ π’ β π‘β
Micro phone
αΆ π
πΎπ‘
+
αΆ π‘ = ππ‘π€, αΆ π‘ = πΎπ‘ αΆ π = ππ‘πΎπ αΆ π, αΆ π = βπΰ·’ πΎπ‘
+π
π‘ π’ : acoustic feature (e.g. ILD, Sound energy) π‘β : desired acoustic feature πΎπ‘
+ : Pseudo-inverse of interaction matrix
αΆ π : control input
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ILD based Aural Servo
- Inter-channel Level Difference (ILD)
- Ratio of two amounts of energy received by each
microphones
- ILD π is approximated as
π = 1 π > 1 π < 1
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ILD based Aural Servo
- Approximating position of sound source ππ‘
- Condition :
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ILD based Aural Servo
- Inter-channel Level Difference (ILD)
- Ratio of two amounts of energy received by each
microphones
- ILD π is approximated as ΰ΅
π2
2
π1
2
Micro phone
αΆ π
πΎπ
+
π πβ
π π’ = π π’ β πβ
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ILD accuracy limitation
- When robot is far from sound source
- π2
2 = π1 2 + (2π¦π‘) 2
- π β β, π1 β π2, π β 1
- ILD π is not significant anymore
ππ ππ ππ π΅ π΅π π΅π π ππ
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ILD accuracy limitation
- When reverberation time is high
- Each microphones ππ perceive an additional energy
from virtual sound sources
- Make error π biased
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ILD accuracy limitation
Accuracy is high only near by the sound source
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+ Absolute sound energy
- Control the distance to the sound source by
setting a desired energy level
- Reverberation has a minor effect when robot is
nearby the sound source
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ILD + Absolute sound energy
- The ILD constrains the orientation of the
microphones while the distance is constrained by the energy level
Micro phone
αΆ π
πΎππΉ
+
π, πΉπ (π, πΉπ)β
π π’ = (π, πΉπ) π’ β (π, πΉπ)β
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- Pioneer 3DX + Two omnidirectional microphones
- Three experiment scenarios
- Typical positioning tasks
- Long range navigation
- Cooperative application
Experiment
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- ππ60 β 580ππ‘, πππ = 20ππΆ, static sound source
- Desired acoustic feature : πβ = 80ππ, πβ = 1
Typical positioning tasks
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Typical positioning tasks
- ππ60 β 580ππ‘, πππ = 20ππΆ, dynamic sound source
- Desired acoustic feature : πβ = 80ππ, πβ = 1
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Long range navigation
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Cooperative application
- UAV led the unicycle ground robot by the sound
from the propellers
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Summary
- Audio-based robot control
- Techniques which uses feedback information
extracted from a aural sensor to control the motion of a robot
- Two acoustic features
- Inter-channel Level Difference (ILD)
- Finding direction of source
- Sound Energy
- Control distance to source