Tunable Multi-Modal Locomotion in Soft Dielectric Elastomer Robots

Soft robots require strong, yet flexible actuators for locomotion and manipulation tasks in unstructured environments. Dielectric elastomer actuators (DEAs) are well suited for these challenges in soft robotics because they operate as compliant capacitors and directly convert electrical energy into mechanical work, thereby allowing for simple design integration at a minimal footprint. In most demonstrations, DEA-based robots are limited to a single mode of locomotion, for example crawling, swimming, or jumping. In this work, we explored a range of actuation patterns in combination with a novel actuator design to enable multi-modal locomotion, whereby an actuation pattern is defined by an actuation voltage (proportional to the applied electric field) and frequency (the actuation rate). We present a DEA robot capable of three different gaits including crawling, hopping, and jumping. In addition, our robot can set itself upright by performing a roll, for example to prepare for the next jump after landing on its side. These results demonstrate that DEAs can be used as versatile experimental devices to validate locomotion models, in both natural and engineered systems.