Efficiency of voluntary closing hand and hook prostheses

Smit, G.; Plettenburg, D.H.

doi:doi:10.3109/03093646.2010.486390

Efficiency of voluntary closing hand and hook prostheses

Title

Efficiency of voluntary closing hand and hook prostheses

Author

Smit, G.
Plettenburg, D.H.

Faculty

Mechanical, Maritime and Materials Engineering

Department

BioMedical Engineering

Date

2010-12-01

Abstract

The Delft Institute of Prosthetics and Orthotics has started a research program to develop an improved voluntary closing, body-powered hand prosthesis. Five commercially available voluntary closing terminal devices were mechanically tested: three hands [Hosmer APRL VC hand, Hosmer Soft VC Male hand, Otto Bock 8K24] and two hooks [Hosmer APRL VC hook, TRS Grip 2SS]. The test results serve as a design guideline for future prostheses. A test bench was used to measure activation cable forces and displacements, and the produced pinch forces. The measurements show that the hands require higher activation forces than the hooks and 1.5 to 8 times more mechanical work. The TRS hook requires the smallest activation force (33 N for a 15 N pinch force) and has the lowest energy dissipation (52 Nmm). The Hosmer Soft hand requires the largest activation force (131 N for a 15 N pinch force) and has the highest energy dissipation (1409 Nmm). The main recommendations for future prostheses are the following: (1) Required activation forces should be below the critical muscle force (~18% of maximum), to enable continuous activation without muscle fatigue. (2) Hysteresis of mechanism and glove should be lowered, to increase efficiency and controllability.

Subject

hand prosthesis
hand prostheses
voluntary closing
hysteresis
efficiency
pinch force
mechanical testing
handprothese
handprothesen
kunstledematen
armprothese
armprothesen
body powered
upper limb
amputation
prosthetics