A large-scale, isoperimetric, untethered, soft robot changes shape by manipulating constant-length inflated tubes using movable joints. For robots to be useful for real-world applications, they must be safe around humans, be adaptable to their environment, and operate in an untethered manner. Soft robots could potentially meet these requirements; however, existing soft robotic architectures are limited by their ability to scale to human sizes and operate at these scales without a tether to transmit power or pressurized air from an external source. Here, we report an untethered, inflated robotic truss, composed of thin-walled inflatable tubes, capable of shape change by continuously relocating its joints, while its total edge length remains constant. Specifically, a set of identical roller modules each pinch the tube to create an effective joint that separates two edges, and modules can be connected to form complex structures. Driving a roller module along a tube changes the overall shape, lengthening one edge and shortening another, while the total edge length and hence fluid volume remain constant. This isoperimetric behavior allows the robot to operate without compressing air or requiring a tether. Our concept brings together advantages from three distinct types of robots—soft, collective, and truss-based—while overcoming certain limitations of each. Our robots are robust and safe, like soft robots, but not limited by a tether; are modular, like collective robots, but not limited by complex subunits; and are shape-changing, like truss robots, but not limited by rigid linear actuators. We demonstrate two-dimensional (2D) robots capable of shape change and a human-scale 3D robot capable of punctuated rolling locomotion and manipulation, all constructed with the same modular rollers and operating without a tether.

中文翻译：

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不受约束的等距软机器人

大型的，等距的，不受限制的，柔软的机器人通过使用活动关节操纵恒定长度的充气管来改变形状。为了使机器人在实际应用中有用，它们必须在人类周围安全，适应环境并以不受束缚的方式运行。软机器人可能满足这些要求。但是，现有的软机器人体系结构受其按比例缩放到人的大小并在没有系绳从外部源传输动力或压缩空气的情况下以这些比例进行操作的能力所限制。在这里，我们报告了一个由薄壁可充气管组成的，不受束缚的，充气的机器人桁架，该桁架可以通过不断重新定位其关节来改变形状，而其总边缘长度保持不变。特别，一组相同的辊子模块，每个辊子都会捏住管子，形成有效的接头，将两个边缘分开，并且可以将模块连接起来以形成复杂的结构。沿管驱动滚子模块会改变整体形状，延长一个边缘并缩短另一个边缘，而总边缘长度和流体体积则保持不变。这种等距行为使机器人可以在不压缩空气或不需要系绳的情况下进行操作。我们的概念融合了三种不同类型的机器人（软机器人，集体机器人和桁架机器人）的优势，同时克服了每种机器人的某些局限性。我们的机器人像软机器人一样坚固，安全，但不受束缚；是模块化的，就像集体机器人一样，但不受复杂的子单元的限制；像桁架机器人一样，形状不断变化，但不受刚性线性致动器的限制。