Don't break a leg: running birds from quail to ostrich prioritise leg safety and economy on uneven terrain.
Don't break a leg: running birds from quail to ostrich prioritise leg safety and economy on uneven terrain.
复制标题
DOI：
10.1242/jeb.102640
复制
发表时间：
2014-11-01
期刊：
影响因子：
--
通讯作者：
Daley MA
中科院分区：
文献类型：
--
作者：
Birn-Jeffery AV;Hubicki CM;Blum Y;Renjewski D;Hurst JW;Daley MA
地面上的爬行鸟类是两足奔跑的典范，从鹌鹑到鸵鸟，它们的体重是其他鸟类的500倍。在这里，我们调查的任务级别的控制优先级，通过分析他们如何谈判的单步障碍，创造了身体稳定性（衰减身体运动的偏差）和一致的腿力长度动态（经济和腿的安全）之间的冲突。我们还测试的假设，即控制优先级之间的身体稳定性和腿部安全性，随着身体尺寸的增加，反映了使用主动控制，以克服与尺寸相关的挑战。重量支持的需求导致转向直腿和僵硬稳定的步态与身体尺寸的增加，但它仍然是未知的非稳定运动的优先事项是否与大小发散。我们发现，所有测量的物种都使用一致的障碍物谈判策略，包括不稳定的身体动力学，以尽量减少腿部姿势和多步负载的波动，而不是直接优先考虑身体稳定性。峰值腿部力量保持显着一致的障碍地形，在0.35的体重水平运行的障碍高度从0.1到0.5倍腿长。所有物种使用类似的立场腿驱动模式，涉及不对称的力长度轨迹和姿势依赖的驱动，以增加或删除能量取决于着陆条件。我们提出了一个简单的立场腿模型，解释了鸟类双足运动的主要特点，并建议经济水平和不平坦的地形作为一个关键的优先事项。我们建议，运行地面鸟类目标的经济性和腿部安全的直接必要的控制密切相关的优先事项，通过适当调整的内在动力学实现足够的稳定性。
Cursorial ground birds are paragons of bipedal running that span a 500-fold mass range from quail to ostrich. Here we investigate the task-level control priorities of cursorial birds by analysing how they negotiate single-step obstacles that create a conflict between body stability (attenuating deviations in body motion) and consistent leg force–length dynamics (for economy and leg safety). We also test the hypothesis that control priorities shift between body stability and leg safety with increasing body size, reflecting use of active control to overcome size-related challenges. Weight-support demands lead to a shift towards straighter legs and stiffer steady gait with increasing body size, but it remains unknown whether non-steady locomotor priorities diverge with size. We found that all measured species used a consistent obstacle negotiation strategy, involving unsteady body dynamics to minimise fluctuations in leg posture and loading across multiple steps, not directly prioritising body stability. Peak leg forces remained remarkably consistent across obstacle terrain, within 0.35 body weights of level running for obstacle heights from 0.1 to 0.5 times leg length. All species used similar stance leg actuation patterns, involving asymmetric force–length trajectories and posture-dependent actuation to add or remove energy depending on landing conditions. We present a simple stance leg model that explains key features of avian bipedal locomotion, and suggests economy as a key priority on both level and uneven terrain. We suggest that running ground birds target the closely coupled priorities of economy and leg safety as the direct imperatives of control, with adequate stability achieved through appropriately tuned intrinsic dynamics.
登录
查看更多内容
影响因子：
--
作者：
CAVAGNA, GA;HEGLUND, NC;TAYLOR, CR
通讯作者：
TAYLOR, CR
影响因子：
56.9
作者：
BIEWENER, AA
通讯作者：
BIEWENER, AA
影响因子：
2.8
作者：
Chang, Young-Hui;Auyang, Arick G.;Nichols, T. Richard
通讯作者：
Nichols, T. Richard
影响因子：
2.4
作者：
BLICKHAN, R
通讯作者：
BLICKHAN, R
影响因子：
2.5
作者：
DIETZ, V;SCHMIDTBLEICHER, D;NOTH, J
通讯作者：
NOTH, J