A rollable structure is advantageous for implementing a small-scale extendable mechanism with a high storage ratio because the structure can be tightly wound around the hub. However, since the radius of the hub determines how flexible the rollable structure should be, the size of the hub typically sets a limit on the highest achievable rigidity. We propose a fan-fold-shaped rollable structure that can enhance structural rigidity without enlarging a hub. The structure, in which multiple panels are connected serially via joints that allow sliding and folding motion, can be unfolded into a zigzag shape for rigidity and folded in layers to be rolled onto the hub. Since the sliding between panels tolerates a perimeter difference under the rolling process, a multiple-layered structure, which scales rigidity, can be wound around the same-sized hub, irrespective of layer count. We also developed a weaving method to fabricate the structure, and the prototype could extend from 386mm to 1936mm and handle 500g at horizontal full extension. Our results indicate an impressively rigid extended arm with high compactness.

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Keywords : #Origami, #Deployable Arm