Jin Fang, Nagasaki Takayuki, Wada Chikamune
Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Japan.
Department of Rehabilitation, Kyushu University of Nursing and Social Welfare, Japan.
J Phys Ther Sci. 2017 Jul;29(7):1171-1175. doi: 10.1589/jpts.29.1171. Epub 2017 Jul 15.
[Purpose] Motion capture system is difficult to use in daily life. The aim of this study was to propose an estimation model for knee and ankle joint angle measurements and locate body center of gravity (COG) of the extension phase during standing-up motion. [Subjects and Methods] Seven healthy male volunteers were enrolled. An estimation model was proposed for the knee and ankle joint angle measurements by combining the angle and acceleration of the trunk, based on readings from the inertial sensor attachment on the subject's chest, during the extension phase. Joint angles and COG position were compared to those obtained by a motion capture system. [Results] The joint angles and COG position demonstrated high correlation coefficients which represent strong correlation between the proposed model and the motion capture system. The proposed model could estimate the joint angle during extension phase, with a maximum error of 4.58 degrees, as well as COG position in the horizontal and vertical directions with maximum errors of 4.48 cm and 3.19 cm, respectively. [Conclusion] The proposed system could be used instead of motion capture system to estimate knee and ankle joint angles; however, the estimation of the COG position was insufficient because of lacked accuracy.
[目的] 运动捕捉系统在日常生活中难以使用。本研究的目的是提出一种用于测量膝关节和踝关节角度的估计模型，并确定起立动作伸展阶段的身体重心（COG）位置。[对象与方法] 招募了7名健康男性志愿者。基于受试者胸部惯性传感器附件的读数，在伸展阶段，通过结合躯干的角度和加速度，提出了一种用于测量膝关节和踝关节角度的估计模型。将关节角度和重心位置与通过运动捕捉系统获得的结果进行比较。[结果] 关节角度和重心位置显示出高相关系数，表明所提出的模型与运动捕捉系统之间存在强相关性。所提出的模型能够估计伸展阶段的关节角度，最大误差为4.58度，还能估计水平和垂直方向的重心位置，最大误差分别为4.48厘米和3.19厘米。[结论] 所提出的系统可用于替代运动捕捉系统来估计膝关节和踝关节角度；然而，由于缺乏准确性，重心位置的估计并不充分。
