Although a wearable assist robot helps to enhance the gait ability of the wearer, it can cause gait instability in an emergency. A collision with an environmental object is one source of such instability. Insufficient adaptation to change by the physical frame, and restriction of joint motion, increases the risk of collision and fall of the wearer owing to the robot. In this article, the reaction motion owing to side contact, which applies a spin moment to the body, is investigated for the wearers of a physical assistant robot. In particular, reaction motions in the horizontal plane, such as body rotation, foot direction, and center-of-mass position, are investigated. Factor analysis and cluster analysis are performed, and two reaction patterns—the rotation group and the straight group—are determined. The motion of these groups suggests an approach for navigation through an obstacle while using an assist robot. Furthermore, the gait phase at collision time is considered as a determinant of the reaction pattern and the reaction pattern is found to affect the fall mode. The results of the article suggest that the joints of the physical assistant robot should be equipped with sufficient degrees of freedom, at least in hip rotation, such that it is capable of rotating the body and feet in the horizontal plane to reduce fall risk.

中文翻译：

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与步态时佩戴的物理辅助机器人的侧面接触导致的恢复运动特征

穿戴式辅助机器人虽然有助于提升穿戴者的步态能力，但在紧急情况下也会造成步态不稳。与环境物体的碰撞是这种不稳定性的来源之一。物理框架对变化的适应性不足，关节运动受到限制，增加了佩戴者因机器人而发生碰撞和跌倒的风险。在本文中，针对物理助手机器人的佩戴者，研究了由于侧面接触而对身体施加旋转力矩的反作用运动。特别地，研究了水平面内的反作用运动，例如身体旋转、足部方向和质心位置。进行因子分析和聚类分析，并确定两种反应模式——旋转组和直线组。这些小组的运动提出了一种在使用辅助机器人的同时通过障碍物导航的方法。此外，碰撞时的步态阶段被认为是反应模式的决定因素，并且发现反应模式会影响跌倒模式。文章的结果表明，物理助理机器人的关节应配备足够的自由度，至少在髋关节旋转方面，使其能够在水平面内旋转身体和脚，以降低跌倒风险。