3D motion tracking for skin deflection, strain and stress analysis Delp Motion lab in Clark Center

Reflective markers (70 total) on arm and skin stretch applicator

Field of view as seen by cameras (red circles show where the applicators would make contact)

Torque versus rotational displacement. Green curves are for skin stretch device with fixed contacts; blue is for freely spinning contacts. As expected, fixed case requires higher torques, corresponding to somewhat higher perceived rotation (and somewhat less comfort at high rotations).

Average displacement of markers Now BLUE curves are for fixed contacts; GREEN is for freely spinning contacts (sorry)… As expected, the average marker displacements are greater for the fixed contact case, correlating with the increase in torque.

Surface plot showing local variations in displacement (at 10 degrees of rotation)

Strain energy GREEN curves are for fixed contacts; BLUE is for freely spinning contacts. As expected, the overall strain energy correlates with the increase in torque and skin displacement (work). Fixed contacts also show local regions of higher strain energy near the contacts.

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.

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.