A Soft Crawling Robot with Layered Hard Scale Structure.

Soft robots possess better adaption to the environment than traditional rigid robots, due to their high compliance and flexibility. Soft crawling robots may be widely applied to travel across complex environment, such as post-disaster search and rescue, environmental exploration, medical surgery, and so on. Soft crawling robots can move forward through elongating and contracting their bodies, but the smooth body surfaces like silicone material have limited their speed of movement. In nature, soft animals use their scales or setae to increase friction anisotropy and propel their bodies forward. Using biologically-inspired skin is an recognized way to increase the movement speed of soft crawling robots effectively. The directionality of the snake scales can produce anisotropic friction with the ground when moving forward, which is necessary to promote the movement of the snake. Inspired by snake scales, we developed a hard scale structure that can be fixed to the bottom of the pneumatic actuators. These scales can generate friction force when in contact with the substrate surface, which increases the speed of this soft crawling robot.