Fast Untethered Soft Robotic Crawler with Elastic Instability

TL;DR

This paper introduces a fast untethered soft robotic crawler inspired by mammalian gait, achieving unprecedented speeds through an innovative elastic instability mechanism and a semi-rigid hair clip chassis.

Contribution

The paper presents a novel soft robot design utilizing an in-plane prestressed hair clip mechanism for high-speed locomotion, significantly surpassing previous soft robot speeds.

Findings

Achieved a crawling speed of 313 mm/s, 5.2 times faster than previous soft robots.

Demonstrated the effectiveness of the hair clip mechanism in enhancing robot speed and strength.

Explored effects of actuation parameters and substrate interactions on robot performance.

Abstract

High-speed locomotion of animals gives them tremendous advantages in exploring, hunting, and escaping from predators in varying environments. Enlightened by the fast-running gait of mammals like cheetahs and wolves, we designed and fabricated a single-servo-driving untethered soft robot that is capable of galloping at a speed of 313 mm/s or 1.56 body length per second (BL/s), 5.2 times and 2.6 times faster than the reported fastest predecessors in mm/s and BL/s, respectively, in literature. An in-plane prestressed hair clip mechanism (HCM) made up of semi-rigid materials like plastic is used as the supporting chassis, the compliant spine, and the muscle force amplifier of the robot at the same time, enabling the robot to be rapid and strong. The influence of factors including actuation frequency, substrates, tethering/untethering, and symmetric/asymmetric actuation is explored with experiments. Based on previous work, this paper further demonstrated the potential of HCM in addressing the speed problem of soft robots.