Crompton R H, Li Y, Alexander R M, Wang W, Gunther M M
Department of Human Anatomy and Cell Biology, University of Liverpool, United Kingdom.
Am J Phys Anthropol. 1996 Apr;99(4):547-70. doi: 10.1002/(SICI)1096-8644(199604)99:4<547::AID-AJPA3>3.0.CO;2-R.
Studies of the dynamics of locomotor performances depend on knowledge of the distribution of body mass within and between limb segments. However, these data are difficult to derive. Segment mass properties have generally been estimated by modelling limbs as truncated cones, but this approach fails to take into account that some segments are of elliptical, not circular, cross section; and further, the profiles of real segments are generally curved. Thus, they are more appropriately modelled as solids of revolution, described by the rotation in space of convex or concave curves, and the possibility of an elliptical cross section needs to be taken into account. In this project we have set out to develop a general geometric model which can take these factors into account, and permit segment inertial properties to be derived from cadavers by segmentation, and from living individuals using linear external measurements. We present a model which may be described by up to four parameters, depending on the profile and serial cross section (circular or ellipsoidal) of the individual segments. The parameters are obtained from cadavers using a simplified complex-pendulum technique, and from intact specimens by calculation from measurements of segment diameters and lengths. From the parameters, the center of mass, moments of interia, and radii of gyration may be derived, using simultaneous equations. Inertial properties of the body segments of four Pan troglodytes and a single Pongo were determined, and contrasted to comparable findings for humans. Using our approach, the mass distribution characteristics of any individual or species may be represented by a rigid-link segment model or "android." If this is made to move according to motion functions derived from a real performance of the individual represented, we show that recordings of resulting ground reaction forces may be quite closely simulated by predictive dynamic modelling.
对运动表现动力学的研究依赖于肢体节段内部和之间体重分布的知识。然而，这些数据很难获得。节段质量特性通常通过将肢体建模为截头圆锥来估计，但这种方法没有考虑到一些节段的横截面是椭圆形而非圆形；此外，实际节段的轮廓通常是弯曲的。因此，它们更适合被建模为旋转体，由凸曲线或凹曲线在空间中的旋转来描述，并且需要考虑椭圆形横截面的可能性。在这个项目中，我们着手开发一个通用几何模型，该模型可以考虑这些因素，并允许通过分割从尸体以及使用线性外部测量从活体个体中得出节段惯性特性。我们提出了一个模型，该模型最多可由四个参数描述，这取决于各个节段的轮廓和连续横截面（圆形或椭圆形）。这些参数通过一种简化的复摆技术从尸体中获得，并通过对节段直径和长度的测量计算从完整标本中获得。从这些参数中，可以使用联立方程得出质心、惯性矩和回转半径。确定了四只黑猩猩和一只猩猩身体节段的惯性特性，并与人类的可比结果进行了对比。使用我们的方法，任何个体或物种的质量分布特征都可以由一个刚性链接节段模型或“人体模型”来表示。如果使其根据从所代表个体的实际表现得出的运动函数移动，则我们表明通过预测动态建模可以相当精确地模拟由此产生的地面反作用力记录。
