Nano Crack-based Angular Potentiometers for Deployable and Small-scale Origami Robots

Origami robots can be fabricated at various scales and transform flat two-dimensional sheets into complex three-dimensional structures. To date, the potential of origami robots in developing versatile robotic systems has been demonstrated through various folding patterns and actuation mechanisms. However, limitations in angle sensing—such as restricted range, direction, and scale—challenge the development of proprioceptive capabilities, hindering their ability to perform tasks. Here, we introduce a nano crack-based angular potentiometer (NanoCAP) capable of detecting a wide range of motion in origami robot joints. NanoCAP provides resistance changes resulting from the opening and closing of cracks under tension and compression. Furthermore, NanoCAP can be fabricated at a small scale, enabling integration into miniaturized origami robots. We validated the proprioceptive capabilities of NanoCAP by measuring angles independent of joint rotation direction, range, and robot size. Demonstrate includes an origami robot manipulator providing real-time posture feedback while transforming from a fully folded flat state to deployment, and a miniature origami gripper capable of detecting subtle angular changes due to external stimuli (e.g., contact with objects).