A Novel Instrument for Estimating Internal Hand Loading from Ezternal Measurements
A new dynamometer was designed to directly measure force vectors in the fingers during grip. These vectors were resolved into overall force magnitude and direction to define the overall grip force. Since the dynamometer was able to measure multiple vectors, the instrument can be used with a biomechanical hand model to estimate tension in the long finger tendons. Sixteen subjects gripped four different cylindrical handles with maximum force. The biomechanical hand model predicted that tendon tension, when normalized by grip force, increased as handle size increases while grip force magnitude decreased. Additionally, the vertical centers of pressure on the handle significantly moved up the handle towards the thumb as handle diameter increased. Another experiment involved sixteen subjects gripping the same four handles at graduated levels of their maximum exertion. Grip force vector angles significantly changed from varying both effort level and handle size. Vertical centers of pressure significantly changed for different handles and for the distal part of the fingers, the vertical center of pressure also changed with effort level. In a final experiment, fourteen subjects used the dynamometer to pull and hold three different loads. Results indicated that grip force was dependent only upon pull force and vector angle was dependent on handle size but not pull force. Vertical centers of pressure significantly changed for handle size. Normalized estimated tendon tension was significant for both handle sizes and pull forces. The new dynamometer and hand model have been shown to be valuable tools and may aid in the design of ergonomic handles.
Curt B. Irwin Robert G. Radwin
University of Wisconsin, Madison, WI USA
国际会议
17th World Congress on Ergonomics(第十七届国际人类工效学大会)
北京
英文
1-4
2009-08-09（万方平台首次上网日期，不代表论文的发表时间）