主动弹性细丝中的姿态选择
Posture selection in active elastic filaments
- Harvard University（哈佛大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文提出一个结合机械平衡与最优控制理论的框架，用于选择主动弹性细丝在重力和流体阻力下的稳定姿态，并揭示控制成本、功能与稳定性间的权衡，成功预测了鳗鱼姿态转变及标度律。
AI中文摘要：
蛇和鳗鱼等细长物体的姿态控制源于被动变形、主动内部驱动和任务级约束之间的相互作用。我们提出一个通用框架，用于在重力和流体阻力产生的分布式力作用下，通过将机械平衡约束与最优控制理论相结合，选择主动弹性细丝的稳定姿态。我们的理论导出了一个最小化描述，其参数控制水动力与重力载荷、弹性和活动性之间的竞争。我们表明，姿态选择反映了控制成本、功能和动态稳定性之间的权衡，导致不同解分支的共存以及它们之间的突变。将该理论应用于水流中的固着鳗鱼，我们重现了实验中观察到的从直立到倾斜姿态的转变，并预测了身体形状和暴露长度的标度律。更一般地，我们的结果为主动细丝如何调节几何形状以在外部场中维持功能提供了统一视角，对生物和人工系统具有启示意义。
英文摘要：
Posture control in slender bodies such as snakes and eels arises from the interplay between passive deformation, active internal actuation, and task-level constraints. We formulate a general framework for the selection of stable postures in active elastic filaments subject to distributed forcing from gravity and fluid drag, by combining the constraints of mechanical equilibrium with optimal control theory. Our theory leads to a minimal description in terms of parameters governing the competition between hydrodynamic and gravitational loading, elasticity, and activity. We show that posture selection reflects a trade-off between control cost, function and dynamical stability, leading to the coexistence of distinct solution branches and abrupt transitions between them. Applying the theory to sessile eels in flow, we recover the experimentally observed transition from upright to reclining postures and predict scaling laws for body shape and exposed length. More generally, our results provide a unified perspective on how active filaments can regulate geometry to maintain function in external fields, with implications for biological and artificial systems.
