Gurram R, Rakheja S, Boileau P E, Gouw G J
CONCAVE Research Centre, Department of Mechanical Engineering, Concordia University, Montreal, Canada.
Cent Eur J Public Health. 1996 Feb;4(1):65-8.
The driving-point mechanical impedance of the human hand-arm system is strongly dependent on the grip force and excitation frequency. In this study, the biodynamic response of the human hand-arm is characterized by three and four degree-of-freedom (DOF) linear and nonlinear mass excited model incorporating grip force dependence of the restoring and dissipative properties. The model parameters are identified by minimizing a constrained objective function compromising impedence magnitude and phase errors between the computed and measured target driving-point mechanical impedance characteristics. The target impedance values are established in the 10 to 1000 Hz frequency range from the measurements performed in the three orthogonal directions (Xh, Yh and Zh) using 2 x g peak acceleration sinusoidal excitation and different magnitudes of constant grip force ranging from 10 to 50 N. The linear and nonlinear models are analyzed to determine the driving-point mechanical impedance characteristics for different levels of grip force. The computed response characteristics are compared to the target values to demonstrate the validity of the proposed models. The results of the study revealed that the four-DOF nonlinear grip force dependent model yields good correlation with the measured response in all three directions, for the range of grip forces considered.
人体手臂系统的驱动点机械阻抗强烈依赖于握力和激励频率。在本研究中，人体手臂的生物动力学响应通过三自由度和四自由度的线性及非线性质量激励模型来表征，该模型考虑了恢复和耗散特性对握力的依赖性。通过最小化一个约束目标函数来确定模型参数，该目标函数兼顾了计算得到的和测量得到的目标驱动点机械阻抗特性之间的阻抗幅值和相位误差。目标阻抗值是在10至1000Hz频率范围内通过在三个正交方向（Xh、Yh和Zh）上进行测量而建立的，测量时使用2倍重力加速度峰值的正弦激励以及10至50N范围内不同大小的恒定握力。对线性和非线性模型进行分析，以确定不同握力水平下的驱动点机械阻抗特性。将计算得到的响应特性与目标值进行比较，以证明所提出模型的有效性。研究结果表明，在所考虑的握力范围内，四自由度非线性握力相关模型在所有三个方向上与测量响应都具有良好的相关性。
