CRII: RI: Embedded and Continuous Shape Morphing using Twisted-and-Coiled Artificial Muscle

许多动物具有在不同环境中移动的能力，例如在陆地上、在水中和在空中。开发具有类似能力的受生物启发的机器人将为机器人学开辟许多新类型的应用。为了实现这一目标，本研究研究了一种新的形状变形方案，该方案可以自动修改结构的形状，例如通过将腿改为鳍状肢。有了形状变形能力，机器人可以利用相同结构的不同形状在不同环境中移动，这可以大幅降低机器人的成本，同时显著提高它们的性能。该方法可以使结构在不使用笨重的外部传感器和执行器的情况下精确地变形为三维形状，使其适合于各种应用，如变形翅膀、多模式机器人、可编程材料、可折叠机器人等。该项目还将通过接触K-12学生、通过受研究启发的项目增强现有课程以及促进本科生研究来广泛影响所有年龄段的STEM学生。新的形状变形方案是通过在软材料中嵌入新颖的扭曲和卷曲执行器(TCA)以及具有随温度变化的刚度的热塑性材料来实现的。在所提出的方案中，该项目的目标是通过TCA的双重驱动和传感能力实现闭环形状控制，从而实现嵌入式和连续的形状变形。要做到这一点，首先将建立基于物理的模型，将所需的结构形状与嵌入的TCA的电阻相关联。然后，可以通过将TCA的电阻控制到所需值来实现闭环形状控制。最后，建议的形状变形方案被应用于一个微型两栖机器人，它可以用直腿在水中游泳，并通过将腿变形成弯曲的形状在地面上行走。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Many animals have the ability to locomote in different environments, such as on land, in the water, and in the air. Developing biologically inspired robots with similar abilities would open up many new types of applications for robotics. Towards this goal, this research investigates a novel shape morphing scheme that can autonomously modify the shape of a structure, such as by changing legs to flippers. With shape morphing capabilities, robots can leverage varying shapes from the same structure for locomotion in different environments, which can drastically reduce the robot's costs while dramatically improving their performance. The approach can enable a structure to precisely morph into a three-dimensional shape without using bulky external sensors and actuators, making it suitable for various applications such as morphing wings, multimodal robots, programmable matter, foldable robots, etc. The project will also broadly impact STEM students of all ages through outreach to K-12 students, enhancement of existing curriculum with research-inspired projects, and promotion of undergraduate research.The new shape morphing scheme is accomplished by embedding a novel twisted-and-coiled actuator (TCA) into soft materials, together with a thermoplastic material with temperature-dependent stiffness. With the proposed scheme, this project aims to accomplish embedded and continuous shape morphing through closed-loop shape control enabled by the TCA's dual actuation and sensing capabilities. To do this, physics-based models will be first established to relate a desired shape of a structure to the embedded TCA's electrical resistance. Then, closed-loop shape control can be accomplished by controlling the TCA's resistance to a desired value. Finally, the proposed shape morphing scheme is applied to a miniature amphibious robot that can swim in water with straight legs and travel on ground by morphing the legs into a curved shape.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.