4D-printed untethered self-propelling soft robot with tactile perception: Rolling, racing, and exploring

Summary Fabricating an intelligent and tactile-sensitive untethered soft robot is a major challenge. In this study, we used 4D printing to manufacture a liquid crystal elastomer-based robot that can realize untethered self-propelled rolling when heated to above 160°C after morphing into a tubule. The curvature of the tubule renders a sustainable directional rolling movement to the robot. A 10-cm-long robot can attain a maximum velocity of more than 48 cm/min on the horizontal plane and climb a slope of approximately 20°. Longer tubules roll faster with improved stability, which ensures the robot's adaptability to complex terrains. Given the flexibility of the material and structure, the tactile sensing ability of the robot is similar to that of the antennae in insects. In addition, the robot can carry a load that is 40 times its own weight, which increases the potential applicability of the proposed robot in the transportation industry.