An active control of foot placement in the frontal plane is required to maintain balance during walking. It has been previously shown that, for walking on stationary structures, the foot is placed at a mediolateral distance from the body centre of mass (CoM) determined by the CoM mediolateral velocity at the instance of heel strike plus some constant offset. However, it is currently unknown whether the same relationship applies in walking on laterally-oscillating structures and to what extent the structural motion and visual conditions govern the pedestrian stepping behaviour in this case. To this end, six healthy subjects walked on a custom-built wide-belt self-paced treadmill with and without sinusoidal mediolateral treadmill motion. The visual environment was either that of a laboratory, or one of two scenes set in an immersive virtual reality (VR) delivered via a head mounted display. The VR scenes differed with respect to the type and amount of visual reference cues enabling the estimation of self-motion. Multilevel statistical modelling is performed on kinematic data on the behaviour of the walkers. It is shown that the foot placement control law based on the mediolateral velocity of the centre of mass applies, and that the lateral structural motion or lack thereof and visual conditions modulate the step width in different ways. Based on these findings, simulations of the inverted pendulum pedestrian model are conducted revealing the influence of parameters defining the foot placement control law on pedestrian-generated lateral forces governing the amplitudes of lateral structural response.

中文翻译：

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在横向振动结构上行走时行人内侧脚放置的决定因素及其对结构稳定性的影响


为了在行走过程中保持平衡，需要主动控制脚在额状面上的位置。先前已经表明，对于在固定结构上行走，脚放置在距身体质心 (CoM) 的中外侧距离处，该距离由脚跟着地时的 CoM 中外侧速度加上一些恒定的偏移量确定。然而，目前尚不清楚相同的关系是否适用于在横向振动结构上行走，以及在这种情况下结构运动和视觉条件在多大程度上控制行人的行走行为。为此，六名健康受试者在定制的宽带自定步速跑步机上行走，有或没有正弦内侧跑步机运动。视觉环境要么是实验室的环境，要么是通过头戴式显示器提供的沉浸式虚拟现实 (VR) 中设置的两个场景之一。 VR 场景在能够估计自我运动的视觉参考线索的类型和数量方面有所不同。对步行者行为的运动学数据进行多级统计建模。结果表明，基于质心的内侧速度的足部放置控制法则适用，并且横向结构运动或缺乏横向结构运动以及视觉条件以不同的方式调节步宽。基于这些发现，对倒立摆行人模型进行了模拟，揭示了定义足部放置控制规律的参数对行人产生的侧向力的影响，侧向力控制着侧向结构响应的幅度。