Organisms can adapt to various complex environments by obtaining optimal morphologies. Plant tendrils evolve an extraordinary and stable spiral morphology in the free-growing stage. By combining apical and asymmetrical growth strategies, the tendrils can adjust their morphology to wrap around and grab different supports. This phenomenon of changing tendril morphology through the movement of growth inspires a thoughtful consideration of the laws of growth that underlie it. In this study, tendril growth is modeled based on the Kirchhoff rod theory to obtain the exact morphological equations. Based on this, the movement patterns of the tendrils are investigated under different growth strategies. It is shown that the self-interference phenomenon appears as the tendril grows, allowing it to hold onto its support more firmly. In addition, a finite element model is constructed using continuum media mechanics and following the finite growth theory to simulate tendril growth. The growth morphology and self-interference phenomenon of tendrils are observed visually. Furthermore, an innovative class of fluid elastic actuators is designed to verify the growth phenomena of tendrils, which can realize the wrapping and locking functions. Several experiments are conducted to measure the end output force and the smallest size that can be clamped, and the output efficiency of the elastic actuator and the optimal working pressure are verified. The results presented in this study could reveal the formation law of free tendril spiral morphology and provide an inspiring idea for the programmability and motion control of bionic soft robots, with promising applications in the fields of underwater rescue and underwater picking.

中文翻译：

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自由生长卷须的干涉形态及自锁结构的应用。


生物体可以通过获得最佳的形态来适应各种复杂的环境。植物卷须在自由生长阶段演化出非凡且稳定的螺旋形态。通过结合顶端和不对称生长策略，卷须可以调整其形态以包裹并抓住不同的支撑物。这种通过生长运动改变卷须形态的现象激发了对其背后生长规律的深思熟虑。在本研究中，基于基尔霍夫杆理论对卷须生长进行建模，以获得精确的形态方程。在此基础上，研究了不同生长策略下卷须的运动模式。结果表明，随着卷须的生长，会出现自干扰现象，使其能够更牢固地抓住支撑物。此外，利用连续介质力学并遵循有限生长理论构建有限元模型来模拟卷须的生长。目视观察卷须的生长形态和自干扰现象。此外，还设计了一类创新的流体弹性执行器来验证卷须的生长现象，从而实现包裹和锁定功能。通过多次实验测量了末端输出力和可夹紧的最小尺寸，验证了弹性执行器的输出效率和最佳工作压力。该研究结果可以揭示自由卷须螺旋形态的形成规律，为仿生软机器人的可编程性和运动控制提供启发性思路，在水下救援和水下拾取领域具有广阔的应用前景。