Fig. 3.
Various basic actuation motions and programmable pseudosequential actuation with multiple degrees of freedom. (A) A 19 cm-long linear zigzag actuator contracts to a compressed structure shorter than 2 cm. The 1D contraction ratio is ∼90%. (B) A 2D origami skeleton using the Miura-ori patterns (area: cm2) can contract to a dense bar-shaped structure (area: cm2). The 2D area contraction ratio approaches 92%. (C) A 3D “magic-ball” origami using the water-bomb pattern (radius: 3.5 cm) contracts to a compacted cylindrical structure (radius: 0.9 cm; height: 6.5 cm). The 3D volume decreases 91% after this contraction. (D) Bending motion can be achieved by using an asymmetrical beam structure as the skeleton. (E) Using a flasher origami pattern as the skeleton, the actuator rotates more than 90 degrees around its center, and its 2D surface contracts by 54% simultaneously. (F) A complex out-of-plane motion combining torsion and contraction can be programed through a 2D Miura-ori origami pattern with select folds weakened. (G) Three fingers on a robotic hand are actuated at different rates using a single control of the internal air pressure. The skeletal structure of this robotic hand is 3D printed from nylon. Different hinge strengths inside the structural voids are designed for these three fingers, which produce significantly different bending stiffnesses: . The bending stiffness of each finger determines its own bending angle at a certain internal pressure level. (H) A bottle of water is gripped, lifted, and twisted by a single-channel vacuum-driven robotic arm. The robotic arm has a modular structure including a cup-shaped gripper and a cylindrical lifter. The gripper uses a polyester magic-ball origami as its skeleton, while a much stiffer compression spring (302 stainless steel) is used as the lifter’s skeleton. When the internal pressure decreases smoothly, the gripping motion will always start first, then the lifting and twisting motions start later as the internal pressure reduces further.