Millard Matthew, Wight Derek, McPhee John, Kubica Eric, Wang David
University of Waterloo, 200 University Avenue, West Waterloo, ON, N2L 3G1, Canada.
J Biomech Eng. 2009 Dec;131(12):121001. doi: 10.1115/1.4000193.
Foot placement has long been recognized as the primary mechanism that humans use to restore balance. Many biomechanists have examined where humans place their feet during gait, perturbations, and athletic events. Roboticists have also used foot placement as a means of control but with limited success. Recently, Wight et al. (2008, "Introduction of the Foot Placement Estimator: A Dynamic Measure of Balance for Bipedal Robotics," ASME J. Comput. Nonlinear Dyn., 3, p. 011009) introduced a planar foot placement estimator (FPE) algorithm that will restore balance to a simplified biped that is falling. This study tested the FPE as a candidate function for sagittal plane human-foot-placement (HFP) by recording the kinematics of 14 healthy subjects while they performed ten walking trials at three speeds. The FPE was highly correlated with HFP (rho>or=0.997) and its accuracy varied linearly from 2.6 cm to -8.3 cm as walking speed increased. A sensitivity analysis revealed that assumption violations of the FPE cannot account for the velocity-dependent changes in FPE-HFP error suggesting that this behavior is volitional.
长期以来，足部放置一直被认为是人类用来恢复平衡的主要机制。许多生物力学家研究了人类在步态、扰动和体育赛事中足部的放置位置。机器人专家也将足部放置用作一种控制手段，但成效有限。最近，怀特等人（2008年，《足部放置估计器的引入：双足机器人平衡的动态测量》，《美国机械工程师学会计算非线性动力学杂志》，第3卷，第011009页）介绍了一种平面足部放置估计器（FPE）算法，该算法能使正在跌倒的简化双足机器人恢复平衡。本研究通过记录14名健康受试者在三种速度下进行十次步行试验时的运动学，测试了FPE作为矢状面人体足部放置（HFP）候选函数的情况。FPE与HFP高度相关（rho≥0.997），并且随着步行速度的增加，其准确性在2.6厘米至 -8.3厘米之间呈线性变化。敏感性分析表明，FPE假设的违背无法解释FPE - HFP误差中与速度相关的变化，这表明这种行为是出于意志的。
