Kinematic data and mathematical modeling of sea star locomotion

It is unclear how animals with radial symmetry control locomotion without a brain. Using a combination of experiments, mathematical modeling, and robotics, we tested the extent to which this control emerges in sea stars from the local control of their hundreds of feet and their mechanical interactions with the body. We discovered that these animals (Protoreaster nodosus) compensate for an experimental increase in their submerged weight by recruiting more feet that synchronize in the power stroke of the locomotor cycle. Mathematical modeling replicated this response to loading in the absence of nervous communication and demonstrated how the body weight serves as a regulator of recruitment. We built a robotic sea star with an array of independently-controlled actuators that were also recruited in greater numbers under higher loads due to their collective mechanics. These findings demonstrate that an array of actuators in biological and robotic systems are capable of cooperative transport with dynamic adjustments to loading. This form of distributed control contrasts the conventional view of animal locomotion as governed by the central nervous system and offers inspiration for the design of engineered devices with arrays of actuators.

Methods
The dataset includes code necessary to acquire and analyze the kinematics of sea -star locomotion. The ressulting data files are included. In addition, we have included the code to mathematically model the mechanics of sea-star locomotion.

辐射对称动物在无大脑的情况下如何调控运动，目前仍尚不明确。本研究结合实验、数学建模与机器人技术，以海星为研究对象，探究其运动调控如何通过数百只管足的局部控制以及与躯体的机械交互实现。研究发现，多棘海盘车（Protoreaster nodosus）会通过募集更多管足，并使这些管足在运动周期的发力冲程中保持同步，来补偿实验中增加的水下负重。数学建模在无神经通讯的条件下复现了这一负重响应，并揭示了躯体重量如何作为募集调控的核心参数。我们搭建了一款搭载独立控制执行器阵列的仿生海星机器人，该机器人同样会因集体力学特性，在更高负重条件下募集更多执行器参与工作。上述研究结果表明，生物与机器人系统中的执行器阵列可通过动态调整适配负重，实现协同运动。这种分布式控制模式与传统认为"动物运动由中枢神经系统主导"的观点相悖，同时为搭载执行器阵列的工程设备设计提供了新的设计灵感。

方法
本数据集包含获取与分析海星运动学所需的代码，同时附带生成的结果数据文件。此外，还提供了用于构建海星运动力学数学模型的代码。