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

许多动物都有能力在不同的环境中移动，比如在陆地上、水中和空中。开发具有类似能力的受生物学启发的机器人将为机器人技术开辟许多新型应用。为了实现这一目标，本研究研究了一种新的形状变形方案，可以自主地改变结构的形状，例如将腿改变为鳍状肢。由于具有形状变形能力，机器人可以利用相同结构的不同形状在不同环境中运动，这可以大大降低机器人的成本，同时显着提高它们的性能。该方法可以使结构精确地变形成三维形状，而无需使用笨重的外部传感器和执行器，使其适用于各种应用，如变形翼，多模态机器人，可编程物质，可折叠机器人等。该项目还将广泛影响所有年龄段的STEM学生，包括向K-12学生推广、以研究为灵感的项目加强现有课程，以及促进本科生的研究。新的形状变形方案是通过将一种新型的扭曲和卷曲致动器（TCA）嵌入软材料以及具有温度相关刚度的热塑性材料来实现的。根据所提出的方案，该项目旨在通过TCA的双驱动和传感功能实现闭环形状控制，实现嵌入式和连续形状变形。为此，将首先建立基于物理的模型，将结构的期望形状与嵌入式TCA的电阻联系起来。然后，通过控制TCA的阻值来实现闭环形状控制。最后，将所提出的形状变形方案应用于一个微型水陆两栖机器人，该机器人可以用直腿在水中游泳，通过将腿变形成弯曲的形状在地面上行走。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.