Sea star inspired crawling and bouncing
Sea star inspired crawling and bouncing
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DOI：
10.1098/rsif.2019.0700
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发表时间：
2020-01-01
影响因子：
3.9
通讯作者：
Kanso, Eva
中科院分区：
文献类型：
--
作者：
Heydari, Sina;Johnson, Amy;Kanso, Eva
海星的口腔表面排列着一排管足，使它们能够在各种地形上实现高度控制的运动。管足的活动是由分布在全身的神经系统协调的，而没有中枢大脑。这样一个分布式的神经系统如何产生协调的运动还有待了解。我们建立了管足和海星星星身体生物力学的数学模型。在该模型中，脚通过其与刚体的结构连接而机械耦合。我们制定的分层控制律，捕捉海星星神经系统的显着特点。也就是说，在管脚水平，功率和恢复冲程遵循状态相关的反馈控制器。在系统级，方向性命令通过神经系统传达给所有管脚。我们研究了这种分层控制模型所提供的运动步态。我们发现，这些最小耦合管脚协调产生强大的向前运动，让人想起海星的爬行运动，在各种地形和异质管脚参数和初始条件。我们的模型还预测了从爬行到弹跳的过渡，与最近的实验一致。最后，我们评论这些研究结果的影响，了解海星的神经力学和自主机器人系统的潜在应用。
The oral surface of sea stars is lined with arrays of tube feet that enable them to achieve highly controlled locomotion on various terrains. The activity of the tube feet is orchestrated by a nervous system that is distributed throughout the body without a central brain. How such a distributed nervous system produces a coordinated locomotion is yet to be understood. We develop mathematical models of the biomechanics of the tube feet and the sea star body. In the model, the feet are coupled mechanically through their structural connection to a rigid body. We formulate hierarchical control laws that capture salient features of the sea star nervous system. Namely, at the tube foot level, the power and recovery strokes follow a state-dependent feedback controller. At the system level, a directionality command is communicated through the nervous system to all tube feet. We study the locomotion gaits afforded by this hierarchical control model. We find that these minimally coupled tube feet coordinate to generate robust forward locomotion, reminiscent of the crawling motion of sea stars, on various terrains and for heterogeneous tube feet parameters and initial conditions. Our model also predicts a transition from crawling to bouncing consistently with recent experiments. We conclude by commenting on the implications of these findings for understanding the neuromechanics of sea stars and their potential application to autonomous robotic systems.