Analysis of handle dynamics-induced errors in hand biodynamic measurements.
Dong-RG; Welcome-DE; McDowell-TW; Wu-JZ
J Sound Vib 2008 Dec; 318(4-5):1313-1333
Reliable experimental data of the driving-point biodynamic response (DPBR) of the hand-arm system are required to develop better biodynamic models for several important applications. The objectives of this study are to enhance the understanding of mechanisms of errors induced via the dynamics of instrumented handles and to identify a relatively more reliable method for DPBR measurement. A model of the handle-hand-arm system was developed and applied to examine various measurement methods. Both analytical and finite element methods were used to perform the examinations. This study found that the handle dynamic response could cause an uneven vibration distribution on its structures, especially at high frequencies (500 Hz), and hand coupling on the handle could influence the distribution characteristics. Whereas the uneven distribution itself could directly result in measurement error, the hand coupling-induced vibration changes could cause errors in tare mass cancellation. The essential reason for both types of error is that the acceleration measured at one point on the handle may not be the same as that distributed at other locations. Because the cap measurement method that separately measures the DPBRs distributed at the fingers and palm can minimize both types of error, it is the best one among the methods examined in this study. The theory developed in this study can be used to help select, develop, and improve the measurement method for a specific application.
Biomechanics; Biomechanical-modeling; Musculoskeletal-system; Humans; Models; Hand-injuries; Arm-injuries; Vibration; Vibration-effects; Vibration-exposure; Biochemical-analysis; Biochemical-indicators
Ren G. Dong, Engineering and Control Technology Branch, National Institute for Occupational Safety and Health, 1095 Willowdale Road, Morgantown, WV 26505
Journal of Sound and Vibration