Dynamic Research on Nonlinear Locomotion of Inchworm-Inspired Soft Crawling Robot

Inchworm-inspired bionic soft crawling robot (SCR) composed of soft materials possesses preeminent active compliant deformation ability and has obvious advantages over traditional hard robots when moving in a confined space, which is up-and-coming candidate in robotic community. Nevertheless, there are rare investigations on dynamic modeling problems of the SCR allowing for its nonlinear deformation properties and frictional contact that affects its crawling performance. In view of this, within the theoretical framework of absolute nodal coordinate formulation, in consideration of material, geometry, and boundary nonlinearities, combining a multiple-point contact model with the Coulomb friction model, an effective and accurate nonlinear dynamic model for a bioinspired SCR with one single limb is proposed to elucidate its motion law. We implement an in-depth dynamic research and analysis on the SCR in terms of average velocity, stick–slip characteristic, gaits and successfully simulate its successive forward crawling locomotion meanwhile gaining dynamic response. The proposed theoretical dynamic model correctly captures the SCR' complex geometry configurations and nonlinear deformations, discloses its stick–slip dynamic behaviors and crawling locomotion mechanism, whose effectiveness and superiority are validated experimentally, which inspires a deep insight to motion analysis of other types of soft robots, and enlightens new ideas of their diversified architecture designs.