Ying Ning, Kim Wangdo
School of Mechanical & Production Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
J Biomech. 2002 Dec;35(12):1647-57. doi: 10.1016/s0021-9290(02)00241-5.
This paper presents a modified Euler angles method, dual Euler angles approach, to describe general spatial human joint motions. In dual Euler angles approach, the three-dimensional joint motion is considered as three successive screw motions with respect to the axes of the moving segment coordinate system; accordingly, the screw motion displacements are represented by dual Euler angles. The algorithm for calculating dual Euler angles from coordinates of markers on the moving segment is also provided in this study. As an example, the proposed method is applied to describe motions of ankle joint complex during dorsiflexion-plantarflexion. A Flock of Birds electromagnetic tracking device (FOB) was used to measure joint motion in vivo. Preliminary accuracy tests on a gimbal structure demonstrate that the mean errors of dual Euler angles evaluated by using source data from FOB are less than 1 degrees for rotations and 1mm for translations, respectively. Based on the pilot study, FOB is feasible for quantifying human joint motions using dual Euler angles approach.
本文提出了一种改进的欧拉角方法，即双欧拉角方法，用于描述一般的空间人体关节运动。在双欧拉角方法中，三维关节运动被视为相对于运动段坐标系轴的三个连续螺旋运动；相应地，螺旋运动位移由双欧拉角表示。本研究还提供了从运动段上标记点坐标计算双欧拉角的算法。作为一个例子，所提出的方法被应用于描述踝关节复合体在背屈-跖屈过程中的运动。使用一群鸟电磁跟踪设备（FOB）在体内测量关节运动。在万向节结构上进行的初步精度测试表明，使用FOB的源数据评估的双欧拉角的平均误差对于旋转分别小于1度，对于平移小于1毫米。基于初步研究，FOB对于使用双欧拉角方法量化人体关节运动是可行的。
