From Hypothesis to Locomotion: A Snail-Inspired Modular Soft Robot

Snails crawl using rhythmic waves of muscular contraction, primarily involving two pedal muscle groups, the dorsoventral and longitudinal muscles. Inspired by pedal muscles of snails, we developed a bioinspired soft robot with modular feet featuring two actuator modules. The dorsoventral actuator enables attachment and detachment in the normal direction, while the longitudinal actuator allows axial contraction and relaxation with omnidirectional steering capability. By sequentially activating these muscle modules, the robot can crawl, steer, and climb. Each longitudinal module includes a controller, electro valves, docking mechanism, communication, and 3-D printed electrical and fluidic channels, creating a modular robophysical platform for studying pedal wave locomotion. Experimental results from robophysical analysis are presented here. First, using snail locomotion principles, we varied wavelength and wave frequency to test normal and rapid gait patterns. Second, the adhesive locomotion and sliding friction of snails through artificial mucus simulant. Third, to extend the robot's reconfigurability, here we demonstrate peristaltic locomotion of earthworms by easily detaching the foot module. This modular platform offers new insights in understanding the movement science of pedal wave locomotion of snails but also extends to study earthworm peristaltic locomotion using soft-body actuation, enabling the robot to achieve effective movement across diverse surfaces.