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Haptic Rendering in Shared Collaborative Environments Transatlantic Touch

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Title: Haptic Rendering in Shared Collaborative Environments Transatlantic Touch


1
Haptic Rendering in Shared/ Collaborative
Environments -Transatlantic Touch
  • CSE 20065160
  • Hwang, Inwook
  • (inux_at_postech.ac.kr)
  • 2006.6.12
  • VRLab, POSTECH

2
Outline
  • Introduction
  • Touch in Shared Virtual Environments
  • Transatlantic Touch
  • Conclusion

3
Introduction Shared Virtual Environment
  • SVE(Shared Virtual Environment) means the virtual
    environment where two or more user can interact
    with each other.
  • Less attention has been paid to human-human and
    human-machine interaction in SVEs.
  • In SVE, the participants can show their actions
    and express their emotions to each other.

4
Introduction Haptic Collaboration
  • Visual and auditory communications are important
    in producing positive effect on the participants
    sensory experience in VE.
  • Then, how about with haptic communication?

5
Outline
  • Introduction
  • Touch in Shared Virtual Environments
  • Transatlantic Touch
  • Conclusion

6
The Ultimate Goal
7
The Goals of This Study
  • To identify the necessary components of touch
    that are required to make a human believe that he
    or she interacts with another human being.
  • To investigate the influence of haptic feedback
    on the task performance and sense of togetherness
    of participants in touch-enabled SVE.

8
Experimental Setup
  • Dual PII 300MHz CPU
  • High-End 3D graphics accelerator
  • SensAble PHANToM
  • To eliminate unstable network delay, PC connected
    to two monitors and two PHANToMs is used.

9
Experimental Design
  • The participants cannot see the partner who is an
    expert user of the system.
  • There were two experimental conditions
  • Visual feedback only (V)
  • Visual and haptic feedback (VH)
  • Group 1 received (VH) first and group 2 received
    (V) first.

10
Scenario and Task

11
Haptic Interaction Models
  • They used a simple spring-damper model.
  • F k?p b?p (k,b coefficient, ?p
    displacement of the cursor)
  • There is no deformation or rotation of object.

12
Results - Performance
  • They scored every trial and used maximum score.
  • (a constant, T total time taken to complete the
    task,
  • R the ratio of error-free time to the T)

13
Results - Togetherness
14
Results - Togetherness
  • For males, higher social anxiety was associated
    with a lower sense of togetherness.
  • For females, higher social anxiety was associated
    with a higher sense of togetherness.
  • Without haptic feedback, participants guessed the
    partner is female.
  • With haptic feedback, participants guessed the
    partner is male.

15
Outline
  • Introduction
  • Touch in Shared Virtual Environments
  • Transatlantic Touch
  • Conclusion

16
Human-Human Haptic Interaction
  • Human-human haptic interaction is different from
    teleoperation.
  • There are no master or slave ends and both
    ends influence each other
  • Users interact mostly in virtual worlds.

17
The Goal of This Study
  • To investigate the influence of haptic feedback
    on the task performance of participants on the
    internet.

18
Experimental Setup -Hardware
  • MIT
  • SensAble PHANToM
  • Dual 0.9GHz PC 256MB RAM
  • Nvidia GeForce 2 based graphic card
  • 19 monitor
  • UCL
  • SensAble PHANToM
  • 1GHz PC 512MB RAM
  • Nvidia GeForce 2 based graphic card
  • 19 monitor

19
Experimental Setup - VR

  • gravity 9.8m/s2

  • mass of the cube 0.1kg

  • friction coefficient 1.0

  • (It simulates contacts between
    medium-hard- rubber and rubber
    surfaces.)

20
Experimental Setup - Network
  • The two sites were connected with Internet2
    network(2.4Gbps)
  • A round-trip delay was approximately 90ms.
  • But, actual packet latency varied.

21
Experimental Setup - Software
  • They used P2P architecture to eliminate the
    latency from intermediate server.
  • The clocks on both systems were synchronized by
    NTP.
  • In every haptic loop, they sent the forces
    applied to the local cube rather than sending the
    position of the probe.
  • Because TCP has significant overhead, they used
    UDP connection in this study.

22
Experimental Design
  • The 20 subjects at UCL were unaware that the
    partner at MIT is an expert user of the system.
  • The subjects were assigned to one of four groups.
  • Subjects were provided with directional
    information or not, and haptic feedback or not.

23
Haptic Interaction Models
  • The motion of the cube is computed by following
    dynamic equation.
  • (m mass, c damping factor, k spring constant,
    position vector of the cube)

24
Network Latency Problem
  • In the presence of transmission delays, force
    feedback has a strong destabilizing effect.
  • In this work, the problem is dealt with by adding
    damping factors at various stages throughout the
    system.

25
Damping Factors
  • Dynamic equation of the cube
  • c, the damping term simulates viscous friction
    forces in the VE.
  • Reaction force equation
  • (k contact stiffness, Ppenetration penetration
    vector)
  • The velocity of hand motion is considered as the
    penetration position between the cube and the
    haptic device.

26
Damping Factors
  • The users interaction with the haptic device
  • With the damping, the users high frequency hand
    tremor can be filtered.
  • The damping works as low-pass filter.

27
Collision Prediction
  • The users hand has much lower motion frequency
    (order of 10Hz) than the sampling frequency of
    the system(1KHz).
  • The motion of the hand can be predicted from the
    history of HIP.

28
Collision Prediction
  • First, we calculate probe-cube vector that is
    connecting the current position to the previous
    position.
  • To remove tremors of the users hand, we take
    several points and average these points. (
    )

29
Collision Prediction
  • Then, we compute distance from the HIP to the
    cube in the direction of the tool path.
  • The computation time for collision check is
    reduced to one distance calculation and one
    comparison.

30
Scenario and Task
  • To lift a virtual cube in a collaborative
    environment in time.

31
Results
  • With the force feedback, subjects felt 5 more
    copresence(?25.4).
  • The use of directional probe reduces
    copresence(?211.85).
  • Age of the subjects negatively associated with
    copresence(?25.9).

32
Outline
  • Introduction
  • Touch in Shared Virtual Environments
  • Transatlantic Touch
  • Conclusion

33
Conclusion
  • Haptic communication produces positive effect on
    the participants sensory experience in VE.
  • They used damping at various stages to eliminate
    instability.

34
Reference
  • C. Basdogan, C.-h. Ho, M. A. Srinivasan, and M.
    Slater, "An Experimental Study on the Role of
    Touch in Shared Virtual Environments," ACM
    Transactions on Computer-Human Interaction, vol.
    7, pp. 443 - 460, 2000.
  • J. Kim, H. Kim, B. K. Tay, M. Muniyandi, M. A.
    Srinivasan, J. Jordan, J. Mortensen, M. Oliveira,
    and M. Slater, "Transatlantic Touch A Study of
    Haptic Collaboration over Long Distance,"
    Presence Teleoperators and Virtual Environments,
    vol. 13, pp. 328 - 337, 2004.
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