Snake bodies are capable of navigating using a wide range of locomotion gaits. Therefore, snake-inspired robots can traverse challenging terrains, move through tight spaces, and perform operations such as inspection, search, and rescue. However, most of the current soft robotic snakes can perform only planar gaits.
Image credit: Dimuthu D. Arachchige et al., arXiv:2010.11476
A recent study proposes a novel type of soft robotic snakes that can bend spatially. That enables them to perform such gaits as serpentine, inward rolling, and outward rolling. The proposed robotic snakes were able to track the spatial shape trajectories for all the gaits. The rolling gait successfully achieved locomotion first time in this type of robot. It was possible by using the friction generated by skin-ground interaction. Unfortunately, the serpentine gait did not produce any meaningful displacement due to the lack of differential friction in the robot skin.
Snakes are a remarkable evolutionary success story. Many snake-inspired robots have been proposed over the years. Soft robotic snakes (SRS) with their continuous and smooth bending capability better mimic their biological counterparts’ unique characteristics. Prior SRSs are limited to planar operation with a limited number of planar gaits. We propose a novel SRS with spatial bending and investigate snake locomotion gaits beyond the capabilities of the state-of-the-art systems. We derive a complete floating-base kinematic model of the robot and use the model to derive jointspace trajectories for serpentine and inward/outward rolling locomotion gaits. The locomotion gaits for the proposed SRS are experimentally validated under varying frequency and amplitude of gait cycles. The results qualitatively and quantitatively validate the SRS ability to leverage spatial bending to achieve locomotion gaits not possible with current SRS.