Hurmuzlu Y, Basdogan C, Carollo J J
Mechanical Engineering Department, Southern Methodist University, Dallas TX 75275.
J Biomech. 1994 Dec;27(12):1495-9. doi: 10.1016/0021-9290(94)90199-6.
Additional graphical tools are needed to better visualize the joint kinematics of human locomotion. Standard plots in which the joint displacements are plotted against time or percent gait cycle do not provide sufficient information about the dynamics of the system. In this article, a study based on the two graphical tools of nonlinear dynamics to visualize the steady-state kinematics of human gait is presented. An experimental setup was developed to acquire the necessary data for application of the techniques. Twenty young adults, whose medical histories are free of gait pathology, were tested. Computerized electrogoniometers and foot switches were used to measure the kinematic data of the lower extremities and capture four instants of the gait cycle: heel strike, foot flat, heel off, and toe off. Phase plane portraits of each joint were constructed for the sagittal plane by plotting angular velocity against angular displacement. Poincaré maps were obtained by periodically sampling the joint profiles at toe off and plotting the ith iterate against the (i + 1)th one. Phase plane portraits are useful in monitoring the variations of joint velocity and position on the same graph in a more compact form. Poincaré maps are effective in differentiating steady gait from transient locomotion.
需要额外的图形工具来更好地可视化人类运动的关节运动学。将关节位移相对于时间或步态周期百分比进行绘制的标准图表无法提供有关系统动力学的足够信息。在本文中，提出了一项基于非线性动力学的两种图形工具来可视化人类步态稳态运动学的研究。开发了一个实验装置来获取应用这些技术所需的数据。对20名无步态病理学病史的年轻人进行了测试。使用计算机化电子测角仪和足部开关来测量下肢的运动学数据，并捕捉步态周期的四个瞬间：脚跟触地、足放平、脚跟离地和脚趾离地。通过绘制角速度与角位移的关系，为矢状面构建每个关节的相平面图。庞加莱映射是通过在脚趾离地时定期对关节轮廓进行采样，并将第i次迭代与第(i + 1)次迭代进行绘制而获得的。相平面图有助于以更紧凑的形式在同一图表上监测关节速度和位置的变化。庞加莱映射在区分稳定步态和瞬态运动方面很有效。
