Architected Elastomers as Load Bearing Actuators for Untethered Soft Robot Walking

Abstract

Abstract Developing fully untethered soft robots that leverage mechanically compliant bodies for robust, adaptable, and bioinspired performance remains a grand challenge. State‐of‐the‐art soft actuators pose major limitations in their force output, power density, energy efficiency, and dependence on bulky, heavy power supplies. These challenges are addressed with electrically driven soft actuators based on motorized, 3D printed architected elastomers. The presented actuators are fully 3D printed from thermoplastic polyurethane (TPU) and have a handed shearing auxetic (HSA) structure. The soft robotic legs are flexible, durable, and driven directly by integrated servo motors. The structure‐property‐performance relationships of HSA legs are explored for soft robot walking by varying the auxetic pattern region of HSAs. Through characterizations of HSA leg performance and soft robot walking, it is demonstrated that soft robotic quadrupeds with the most mechanically compliant legs achieve the fastest walking speed (183 mm s −1 or 0.65 body lengths per second) and the lowest cost of transport—despite generating the lowest forces. It is anticipated that this work will spark new directions in the optimized design and manufacturing of soft actuators for untethered locomotion and the creation of deployable soft robots that can practically operate in unstructured, real‐world environments.