An Untethered Soft Snail Robot Steers with a Single Motor.

Abstract

Achieving strong adaptability and high-load capacity for small-scale soft robots remains a challenge in current robotics engineering. In this study, inspired by a snail movement, we developed a soft crawling robot capable of controllable locomotion and carrying a load of 204 g-7.7 times its own weight-using just one single motor for robot control. The robot measures 7.6 cm in length, 3 cm in width, and 2.5 cm in height, with a total weight of 26.5 g. The anisotropic friction mechanism on the robot's bottom, comprising a soft origami-based pad and asymmetrical sawtooth structure, enables its strong adhesion to stick to and simultaneously crawl (transitional adhesion) on many surfaces. This design allows the robot to move at speeds up to 3 mm/s and climb a slope of 35° inclinations, also making it suitable for various uneven terrains. Additionally, the robot has enhanced cross-environmental capabilities due to its ability to glide on the water. This research advances the development of relatively simple small-scale single-actuator robots, providing insights into their potential for flexible movement, high-load capacity, and potential swarming behavior.