Inchworm-Inspired Soft Robot With Light-Actuated Locomotion

In this work, a light-actuated inchworm-inspired soft robot capable of directional locomotion has been proposed, developed, and characterized. The robot is designed and divided into three parts according to the functions during locomotion, which are the body, front leg, and back leg. The body of inchworm should provide contraction and stretching force. Thus, bilayer reduced graphene oxide and graphene oxide-polydopamine soft film is fabricated acting as robot body since it could implant light-induced deformation rapidly when stimulated. When applying near-infrared laser on it, bending would generate and unbending would take place after withdrawing laser, which imitates the longitudinal body muscle controlling contraction and stretching behavior of the inchworm during locomotion. Besides, robot legs are designed owning different heights and contact angles to the ground. Due to such structure, the directional movement could be realized. Then, by coordinating the body and two legs, the robot achieves a biomimetic inchworm gait. Experiments are carried out to characterize the robot body's light sensitivity as well as the robot's locomotive performance. As the experiment results showed, robot body bends at a speed of 17 °/s when laser is applied on it and the whole robot could realize forward locomotion mimicking inchworm by applying laser light periodically. The step length during one locomotion cycle could achieve 0.6 mm, which is 1/10 of body length.