Humans plan for the near future to walk economically on uneven terrain.
Humans plan for the near future to walk economically on uneven terrain.
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DOI：
10.1073/pnas.2211405120
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发表时间：
2023-05-09
影响因子：
11.1
通讯作者：
中科院分区：
文献类型：
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作者：
人类在行走时显然会向前看，但我们不知道他们会对不平坦的地形做出什么样的调整，以及为了什么目的。我们表明，人类有目的地（尽管是下意识地）计划和调整他们的前进速度，即将到来的地形，预测的能量消耗最小化。这项研究表明，步行的动力学、能量学和控制是可以预测的。人类对身体与世界的相互作用的预测和推理能力比以前所了解的更强。他们利用这种能力来规划复杂的控制序列，以节省能源。人类在不平坦的地形上行走时，步态会出现微小的波动。波动偏离了稳定的，能量最小化的水平行走模式，没有明显的组织。但人类在行走时经常向前看，并可能计划地形的预期波动。只有当这种规划服务于某种客观目的时才是明智的，例如保持恒定的速度或减少能源消耗，这在有限的规划能力内也是可以实现的。在这里，我们表明，人类计划和执行最佳控制策略在不平坦的地形。他们不是保持恒定的速度，而是有目的地进行预期的速度调整，以最大限度地减少能量消耗。一个简单的最优控制模型预测经济速度波动，与人类（N = 12）在七种不同地形剖面（与模型相关，所有地形）上行走的实验非常一致。 参与者在每个地形特征前大约6到8步开始进行可重复的速度波动（每步最多±7.5厘米的高度差，最多16个连续的特征）。更近的特征更重要，因为能量随着每一步与地面的碰撞而消散，阻止了动量无限期地持续下去。因此，有限的连续前瞻视野和电机工作空间足以对任何长度的地形进行实际优化。人类在不久的将来会行走，以规划复杂的最佳控制序列。
Humans obviously look ahead as they walk, but it is unknown what adjustments they make for uneven terrain and for what objective. We show that humans purposefully (albeit subconsciously) plan and adjust their forward speed ahead of upcoming terrain, as predicted by minimization of energy expenditure. This research shows how the dynamics, energetics, and control of walking are predictable. Humans have greater capacity to anticipate and reason about the body’s interactions with the world than previously understood. They use this capacity to plan complex control sequences that save them energy. Humans experience small fluctuations in their gait when walking on uneven terrain. The fluctuations deviate from the steady, energy-minimizing pattern for level walking and have no obvious organization. But humans often look ahead when they walk, and could potentially plan anticipatory fluctuations for the terrain. Such planning is only sensible if it serves some an objective purpose, such as maintaining constant speed or reducing energy expenditure, that is also attainable within finite planning capacity. Here, we show that humans do plan and perform optimal control strategies on uneven terrain. Rather than maintaining constant speed, they make purposeful, anticipatory speed adjustments that are consistent with minimizing energy expenditure. A simple optimal control model predicts economical speed fluctuations that agree well with experiments with humans (N = 12) walking on seven different terrain profiles (correlated with model , all terrains). Participants made repeatable speed fluctuations starting about six to eight steps ahead of each terrain feature (up to ±7.5 cm height difference each step, up to 16 consecutive features). Nearer features matter more, because energy is dissipated with each succeeding step’s collision with ground, preventing momentum from persisting indefinitely. A finite horizon of continuous look-ahead and motor working space thus suffice to practically optimize for any length of terrain. Humans reason about walking in the near future to plan complex optimal control sequences.
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DOI：
10.1073/pnas.2020327118
发表时间：
2021-07-20
影响因子：
11.1
作者：
Brown GL;Seethapathi N;Srinivasan M
通讯作者：
Srinivasan M
DOI：
10.1242/jeb.102640
发表时间：
2014-11-01
期刊：
The Journal of experimental biology
影响因子：
--
作者：
Birn-Jeffery AV;Hubicki CM;Blum Y;Renjewski D;Hurst JW;Daley MA
通讯作者：
Daley MA
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影响因子：
3.8
作者：
Higuchi T
通讯作者：
Higuchi T
影响因子：
64.8
作者：
Harris, CM;Wolpert, DM
通讯作者：
Wolpert, DM
影响因子：
4.6
作者：
Darici, Osman;Temeltas, Hakan;Kuo, Arthur D.
通讯作者：
Kuo, Arthur D.