Active control of lateral balance in human walking
Active control of lateral balance in human walking
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DOI：
10.1016/s0021-9290(00)00101-9
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发表时间：
2000-11-01
影响因子：
2.4
通讯作者：
Kuo, AD
中科院分区：
文献类型：
--
作者：
Bauby, CE;Kuo, AD
我们测量了步态过程中足部位置的变化，以测试是否必须主动控制侧向平衡以防止动态不稳定。该假设是使用一个简单的动力学模型开发的，该模型可以以类似于人类的周期性步态走下一个轻微的斜坡。这种步态是完全被动的，除了它需要主动控制一个单一的不稳定模式，主要限于横向运动。控制这种不稳定性的一种特别有效的方法是调整脚的外侧位置。我们假设，类似的主动反馈控制是由人类进行的，前后动态稳定被动或非常低的水平控制。该模型预测，主动反馈回路中的不确定性应导致足部放置的变化性，横向大于纵向。此外，感觉信息的丢失，例如通过闭上眼睛，应该会导致横向变异性的较大增加。控制模型还预测了步长和步长之间的轻微耦合。我们测试了15名年轻的正常人受试者，发现睁眼时的横向变异性比前后变异性大79%，闭眼时的横向变异性增加更大（53%比21%），与模型的预测一致。我们还发现，横向和前后脚放置之间的耦合与控制模型预测的值0.13一致。我们的研究结果意味着，人类可以利用被动的动态特性的四肢在矢状面，但必须提供显着的主动控制，以稳定的横向运动。(C)2000爱思唯尔科技有限公司版权所有。
We measured variability of foot placement during gait to test whether lateral balance must be actively controlled against dynamic instability. The hypothesis was developed using a simple dynamical model that can walk down a slight incline with a periodic gait resembling that of humans. This gait is entirely passive except that it requires active control for a single unstable mode, confined mainly to lateral motion. An especially efficient means of controlling this instability is to adjust lateral foot placement. We hypothesized that similar active feedback control is performed by humans, with fore-aft dynamics stabilized either passively or by very low-level control. The model predicts that uncertainty within the active feedback loop should result in variability in foot placement that is larger laterally than fore-aft. In addition, loss of sensory information such as by closing the eyes should result in larger increases in lateral variability. The control model also predicts a slight coupling between step width and length. We tested 15 young normal human subjects and found that lateral variability was 79% larger than fore-aft variability with eyes open, and a larger increase in lateral variability (53% vs. 21%) with eyes closed, consistent with the model's predictions. We also found that the coupling between lateral and fore-aft foot placements was consistent with a value of 0.13 predicted by the control model. Our results imply that humans may harness passive dynamic properties of the limbs in the sagittal plane, but must provide significant active control in order to stabilize lateral motion. (C) 2000 Elsevier Science Ltd. All rights reserved.