Balancing on a narrow ridge: biomechanics and control
Balancing on a narrow ridge: biomechanics and control
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DOI：
10.1098/rstb.1999.0439
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发表时间：
1999-05-29
影响因子：
6.3
通讯作者：
Otten, E
中科院分区：
文献类型：
--
作者：
Otten, E
站立的人的平衡通常用倒立摆模型来解释。在这个模型中，受试者调用一个水平的地面反作用力，并通过改变脚下压力中心的位置来控制它。在实验中，我展示了人类能够单脚站立在只有几毫米宽的山脊上几分钟。在本文中，我研究了倒立摆模型是否能够解释这一成果。我发现主体的质心偏离了支撑表面，使得倒立摆模型不充分。通过对人体动力学的逆模拟，我发现站立腿的髋关节力矩被用来改变地面反作用力的水平分量。这个力把重心拉回到支撑物的表面上。受试者在摆动腿的髋关节、肩关节和颈部产生力力矩。这些时刻与站立腿的臀部策略一起工作，以限制头-臂-躯干综合体的角加速度。瞬间变化的同步性表明，受试者使用的是运动程序，而不是长潜伏期反射。
The balance of standing humans is usually explained by the inverted pendulum model. The subject invokes a horizontal ground-reaction force in this model and controls it by changing the location of the centre of pressure under the foot or feet. In experiments I showed that humans are able to stand on a ridge of only a few millimetres wide on one foot for a few minutes. In the present paper I investigate whether the inverted pendulum model is able to explain this achievement. I found that the centre of mass of the subjects sways beyond the surface of support, rendering the inverted pendulum model inadequate. Using inverse simulations of the dynamics of the human body I found that hip-joint moments of the stance leg are used to vary the horizontal component of the ground-reaction force. This force brings the centre of mass back over the surface of support. The subjects generate moments of force at the hip-joint of the swing leg, at the shoulder-joints and at the neck. These moments work in conjunction with a hip strategy of the stance leg to limit the angular acceleration of the head-arms-trunk complex. The synchrony of the variation in moments suggests that subjects use a motor programme rather than long latency reflexes.