Grounded running in quails: Simulations indicate benefits of observed fixed aperture angle between legs before touch-down
Grounded running in quails: Simulations indicate benefits of observed fixed aperture angle between legs before touch-down
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DOI：
10.1016/j.jtbi.2013.06.031
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发表时间：
2013-10-21
影响因子：
2
通讯作者：
Blickhan, Reinhard
中科院分区：
文献类型：
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作者：
Andrada, Emanuel;Rode, Christian;Blickhan, Reinhard
许多鸟在很大的速度范围内使用接地跑步(没有空中阶段)。与步行和跑步相反，基于BSLIP(两足弹簧加载倒立摆)模板的这种步态的数值研究很少。为了获得与模板相关的参数(如腿部僵硬)，我们使用了X射线摄影结合地面反作用力的测量。有趣的是，在速度上，鹌鹑并没有调整摆动腿相对于地面的攻角，而是调整了腿之间的角度(我们称之为孔径角)，并在触地前大约30毫秒固定了它。在与BSLIP的模拟中，我们将这种摆动腿对齐策略与文献中通常使用的相对于地面的固定攻角进行了比较。我们发现对称的周期接地运行在一个单连通的子集上，这个子集占所研究参数空间的三分之一。固定光圈角度策略显示了改进的局部稳定性和对大扰动的惊人容忍度。从周期解开始，经过10%的腿部休息长度的阶跃上升或阶跃下降扰动，在绝大多数情况下，两足滑移可以完成至少50步的下降。固定的攻角策略是不可行的。我们提出，特别是在小动物中，接地跑步可能是一种常见的步态，它允许高度顺应的系统利用能量存储，而不需要在面临扰动时快速改变运动程序。(C)2013爱思唯尔有限公司。保留所有权利。
Many birds use grounded running (running without aerial phases) in a wide range of speeds. Contrary to walking and running, numerical investigations of this gait based on the BSLIP (bipedal spring loaded inverted pendulum) template are rare. To obtain template related parameters of quails (e.g. leg stiffness) we used x-ray cinematography combined with ground reaction force measurements of quail grounded running. Interestingly, with speed the quails did not adjust the swing legs angle of attack with respect to the ground but adapted the angle between legs (which we termed aperture angle), and fixed it about 30 ms before touchdown. In simulations with the BSLIP we compared this swing leg alignment policy with the fixed angle of attack with respect to the ground typically used in the literature. We found symmetric periodic grounded running in a simply connected subset comprising one third of the investigated parameter space. The fixed aperture angle strategy revealed improved local stability and surprising tolerance with respect to large perturbations. Starting with the periodic solutions, after step-down step-up or step-up step-down perturbations of 10% leg rest length, in the vast majority of cases the bipedal SLIP could accomplish at least 50 steps to fall. The fixed angle of attack strategy was not feasible. We propose that, in small animals in particular, grounded running may be a common gait that allows highly compliant systems to exploit energy storage without the necessity of quick changes in the locomotor program when facing perturbations. (C) 2013 Elsevier Ltd. All rights reserved.