3D motion tracking for skin deflection, strain and stress analysis

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3D motion tracking for skindeflection, strain
and stress analysis
Delp Motion lab in Clark Center
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Reflective markers (70 total)on arm and skin
stretch applicator
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Field of view as seen bycameras (red circles
show wherethe applicators would make contact)
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Torque versus rotational displacement.
Green curves are forskin stretch devicewith
fixed contacts blue is for freelyspinning
contacts.As expected, fixedcase requires
higher torques,corresponding tosomewhat
higherperceived rotation(and somewhatless
comfort at high rotations).
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Average displacement of markers
Now BLUE curves arefor fixed contacts GREEN is
for freelyspinning contacts (sorry) As
expected, theaverage markerdisplacements
aregreater for the fixedcontact case,
correlating with theincrease in torque.
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Surface plot showing local variationsin
displacement (at 10 degrees of rotation)
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Strain energy
GREEN curves arefor fixed contacts BLUE is for
freelyspinning contacts. As expected,
theoverall strainenergy correlateswith
theincrease in torqueand skin
displacement(work). Fixed contacts alsoshow
local regionsof higher strainenergy near the
contacts.
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Update KAUST project(Jason Wheeler)

• Getting ready to do realtime feedback for motion
  training application (e.g., ACL injury) with
  Prof. Thor Besier
• Currently doing software integration motion
  capture ? motion processing and estimation of
  tendon forces, motions ? feedback via skin
  stretch.

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Novint (Cutkosky, Salisbury)

• NOVINT Inc. (makers of the Novint Falcon haptic
  feedback device, which is inspired by the Force
  Dimension Omega) have contacted us about possible
  designs for a 6 DOF version with 3 DOF wrist.
• Meeting will be Dec. 15.