07/11/07 1
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
07/11/07 2
Outline
•Context•Contact states and events•Computation •Multimodal feedback
– Visual– Audio– 6DOF Haptic
•Conclusion
OUTLINE
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Outline
•Context•Contact states and events•Computation •Multimodal feedback
– Visual– Audio– 6DOF Haptic
•Conclusion
OUTLINE
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Context
•Virtual contact between objects– Virtual prototyping– Assembly/Maintenance simulations– Video games– …
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Context
•Multimodal rendering of contact– Visual– Audio– Haptic
•Some limitations– Computational resources– Sensor resolution
500 Hz1 kHz48 kHz60Hz
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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 FrictionImpact 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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Outline
•Context•Contact states and events•Computation •Multimodal feedback
– Visual– Audio– 6DOF Haptic
•Conclusion
OUTLINE
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Computation of contact states and events
•The contact condition :
•The events are defined by :– Impact :
– Detachment :
Local linear velocity
Normal
FrictionImpact 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…
FrictionImpact 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 ?