Soft and Fast Hopping-Running Robot with Speed of Six Times Its Body Length per Second

Existing robots capable of hopping or running mostly rely on rigid actuators, but soft hopping or running robots based on muscle-like actuators have not yet been achieved. In this article, we report a tethered soft robot capable of hopping-running on smooth and rough surfaces with high speed. The hopping-running robot is composed of two soft joints that simulate the foreleg and hind leg driven by dielectric elastomer. The mass, length, width, and height of the robot are 6.5 g, 8.5 cm, 4.8 cm, and 50 cm, respectively. The robot can run at a speed of 51.83 cm/s (6.10 body lengths/s), which is much faster than previously reported locomotion robots driven by soft responsive materials. The robot also shows good adaptability to different terrains, such as marble, wood, rubber, sandpaper, and slopes. The robot can carry a load equal to its weight, can maintain a high locomotion speed, and demonstrates the potential ability to carry its power supply and control circuitry.