Legless Squamate Reptiles Inspired Design: Simple Soft Crawling Actuator

This paper presents a novel pneumatic soft crawling actuator that exploits scale-like chassis to move. Based on the lateral undulation movement, bellows-type actuators are designed with embedded fluidic chambers that produce bidirectional bending when pressurized. Three chassis structures are created and manufactured to simulate the anisotropy friction by analyzing the legless squamate reptile motion principle. Inspired by the rigid snake robot modeling, a framework to solve the dynamic behavior problem of a soft crawling actuator is further modeled. Particularly, the expected movement has been achieved. Through quantitative analysis, the horizontal belt type shows a more effective drive. Locomotion experimental results of the soft crawling actuator prototype on a carpeted surface show good agreement with model predictions. The demonstrations of terrain adaptability prove movement ability in complicated and constrained environments such as a steep slope, ladders surface, and step surface.