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Using an Event-Based Approach to Improve
the Multimodal Rendering of
6DOF Virtual Contact
Jean Sreng, Florian Bergez, Jérémie Le Garrec,
Anatole Lécuyer, Claude Andriot
[email protected]
07/11/07
1
Outline
• Context
• Contact states and events
• Computation
• Multimodal feedback
– Visual
– Audio
– 6DOF Haptic
• Conclusion
OUTLINE
07/11/07
2
Outline
• Context
• Contact states and events
• Computation
• Multimodal feedback
– Visual
– Audio
– 6DOF Haptic
• Conclusion
OUTLINE
07/11/07
3
Context
• Virtual contact between objects
–
–
–
–
Virtual prototyping
Assembly/Maintenance simulations
Video games
…
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Context
• Multimodal rendering of contact
– Visual
– Audio
– Haptic
60Hz
48 kHz
1 kHz
500 Hz
• Some limitations
– Computational resources
– Sensor resolution
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Context
• To overcome these limitations :
– Sound synthesis algorithms (modal synthesis)
[van den doel et. al.]
– Event-based haptic [kuchenbecker et. al.]
–…
• However :
– Often tied to a specific physical engine
– Demonstrated in a simple context
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We propose…
• An event-based approach :
– Integrate various techniques
• Visual
• Audio
• 6DOF Haptic
– Based only on position information
• Not to be tied to a specific physical engine
• Can be easily adapted to an existing simulation
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Outline
• Context
• Contact states and events
• Computation
• Multimodal feedback
– Visual
– Audio
– 6DOF Haptic
• Conclusion
OUTLINE
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Contact information (states)
• Continuous, “time independent” states :
– Free motion (no contact)
– Friction (contact)
Free motion
Friction
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Contact information (events)
• Discrete events describing the “evolution” :
– Impact
– Detachment
Free motion
Impact
Friction
Detachment
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Contact information (states and events)
• The classic continuous information :
– Is essential to graphic and closed-loop haptic
rendering
– Cannot convey efficiently the transient nature of
an impact
• The different states and events information can
be used to improve the rendering of :
– Transient phenomena (impact)
– Continuous phenomena (friction)
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11
Outline
• Context
• Contact states and events
• Computation
• Multimodal feedback
– Visual
– Audio
– 6DOF Haptic
• Conclusion
OUTLINE
07/11/07
12
Computation of contact states and events
Impact
Friction
Detachment
• The contact condition :
Local linear
velocity
Normal
• The events are defined by :
– Impact :
– Detachment :
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Velocity computation
• To estimate the velocity :
• Some issues :
– Time stepping
– Approximation errors
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Computation of contact states and events
• On the timestep
– Impact event :
– Friction state :
– Detachment event :
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Computation of contact states and events
• In a nutshell…
Impact
Friction
Detachment
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Outline
• Context
• Contact states and events
• Computation
• Multimodal feedback
– Visual
– Audio
– 6DOF Haptic
• Conclusion
OUTLINE
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Multimodal feedback
• The generated states and events can be used
with specific rendering techniques
• Implementation on an existing 6DOF haptic
simulation
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Visual feedback
• Particle effect :
– Impact event
– Friction state
– Detachment event
• Pencil effect on friction state :
– Color : Force
– Thickness : Velocity
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Audio feedback
• Modal synthesis of impact event and friction state :
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Haptic feedback
• 6DOF event-based haptic feedback of impact event
– Traditional closed loop feedback
– High frequency force pattern
Elementary wrench associated to an
impact point
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Haptic feedback
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Conclusion
• We proposed :
– An event-based approach to improve the
rendering of contact :
• Impact
• Friction
• Detachment
– A computation method based only on object’s
positions
– A multimodal implementation on a complex
virtual prototyping simulation
• Visual
• Audio
• 6DOF Haptic
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Further work
• A formal user evaluation
– Compare with traditional feedback
– Complex industrial context
• Test some other feedback :
– Detachment event
– 6DOF haptic texture
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Questions
Thank you for listening
Questions ?
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