Bioinspired multimodal soft robot driven by a single dielectric elastomer actuator and two flexible electroadhesive feet

Locomotion is an important ability of animals and bioinspired mobile robots. It is, however, challenging for current soft mobile robots to achieve multimodal locomotion within a simple structure. Inspired by caterpillars, we combine a two-degree-of-freedom (2-DOF) dielectric elastomer actuator (DEA) and two flexible electroadhesives (EAs) to form the multimodal soft robot. The 2-DOF DEA was regarded as the deformable body that can elongate, contract, and bend. The EAs, fabricated by a cost-effective cut-transfer method, acted as two feet that can provide required and sufficient frictions whilst moving on different surfaces. Both the DEA and EA were experimentally characterized. As a result, we developed a caterpillar inspired soft robot capable of multimodal turning, crawling, and climbing. The robot was able to crawl at a speed of 2.38 mm/s, achieve two turning modes, climb at a speed of 2.30 mm/s, and can still function after 10000 operation cycles. The robot was further demonstrated to carry a micro camera for inspection tasks in a narrow tunnel, and it may be possible to deploy the robot on satellites for detection uses. This study provides a new insight for the design of bioinspired soft robots with multimodal locomotion capabilities.