Article

Cosmetic gloves that cover a prosthetic hand have a parasitic
positive stiffness that counteracts the flexion of a finger joint. OBJECTIVES:
Reducing the required input torque to move a finger of a prosthetic hand by
compensating the parasitic stiffness of the cosmetic glove. STUDY DESIGN:
Experimental, test bench. METHODS: The parasitic positive stiffness and the
required input torques of a polyvinyl chloride glove and a silicone glove were
measured when flexing a metacarpophalangeal finger joint for 90 degrees . To
compensate this positive stiffness, an adjustable compensation mechanism with a
negative stiffness was designed and built. A MATLAB model was created to predict
the optimal settings of the mechanism, based on the measured stiffness, in order
to minimize the required input torque of the total system.
The mechanism was
tested in its optimal setting with an applied glove. RESULTS: The mechanism
reduced the required input torque by 58% for the polyvinyl chloride glove and by
52% for the silicone glove. The total energy dissipation of the joint did not
change significantly. CONCLUSIONS: This study shows that the undesired positive
stiffness in the joint can be compensated with a relatively simple negative
stiffness mechanism, which fits inside a finger of a standard cosmetic glove.
Clinical relevance This study presents a mechanism that compensates the undesired
stiffness of cosmetic gloves on prosthetic hands.
As a result, it requires less
input force, torque and energy to move the fingers. Application of this mechanism
in body-powered hands will reduce the control effort of the user.

Langue : ANGLAIS