Development of hand-arm system models for vibrating tool analysis and test rig construction.
Dong RG; Welcome DE; Wu JZ; McDowell TW
Noise Control Eng J 2008 Jan-Feb; 56(1):35-44
The vibration and noise generated by powered hand tools may be affected by human interaction with these tools. This effect can be taken into account by including a hand-arm system model in tool analysis and testing. The objective of this study is to propose a general methodology for developing practical models for tool analyses and test rig constructions. To demonstrate the methodology, this study applied three traditional models (2-, 3-, and 4-degree-of-freedom (DOF) models) as well as a new 4-DOF model proposed by the authors. The biodynamic responses to hand-transmitted vibration measured at the hand driving-point along the forearm direction under combined grip and push actions were used to determine the parameters of the models using a least root-mean-square error curve fitting method. This study found that the new 4-DOF model and the traditional 3-DOF and 4-DOF models accurately represented the experimental mechanical impedance (MI). The transmissibility functions predicted using these models were also consistent with their corresponding experimental data measured on the fingers and at the wrist. When judged using apparent mass (AM) instead of MI, the traditional 2-DOF model also fits the experimental data well. The parameters of the 2-DOF and new 4-DOF models are more reasonable than those of the other two models for test rig construction. This study concluded that the new 4-DOF model provides the best choice for analyzing tools and for constructing test rigs. However, if the hand-tool dynamic interactions below 100 Hz are of major concern, the 2-DOF model is simpler and less expensive for test rig construction. Whereas these two models can be directly used in some applications, the proposed methodology can be used to develop a more tool-specific model when biodynamic response data for the specific tool are available.
Construction-equipment; Power-tools; Mathematical-models; Laboratory-testing; Laboratory-techniques; Laboratory-equipment; Biological-effects; Biomechanical-engineering; Biomechanical-modeling; Biomechanics; Analytical-processes; Models; Analytical-models; Vibration
RG Dong, NIOSH, Engineering & Control Technol Branch, 1095 Willowdale Rd, MS L-2027, Morgantown, WV 26505
Noise Control Engineering Journal