DESIGN AND DYNAMIC ANALYSIS OF A NOVEL BIO-INSPIRED ERECTING STRUCTURE

Since organisms can accomplish specific tasks through various motion forms, bionic design methods have been received extensive attention from scholars. Inspired by the fact that earthworms have excellent mobility and adaptability in a variety of environments, earthworm-like robots have been proposed and applied in search and rescue, medical treatment and other fields. However, existing earthworm-like robots generally realize rectilinear motion through axial deformation of its body segments, which cannot be applied to realize the erecting function of snake organisms. In order to solve the problem that existing earthworm-like robot cannot erect, a bio-inspired flexible joint with nonlinear multi-stable property is proposed. Based on the proposed bio-inspired flexible joint, a multi-segment bio-inspired erecting structure is built to realize the erecting function of inchworms, snakes and other organisms. First, the model of the bio-inspired erecting joint is proposed. The potential energy of multi-segment bio-inspired erecting structure is obtained, and the dynamic model of the multi-segment bio-inspired erecting structure is established. Then, based on the potential energy and extremum principle, the structural design criteria is proposed to realize required erecting configuration. The effectiveness of structural design criteria is verified and the condition to trigger required configuration is studied by using the dynamic model. Finally, according to different design requirement for the number of erecting segments, corresponding bio-inspired erecting structure is designed. The results show that the design criteria of structural parameters can make the multi-segment bio-inspired erecting structure reach the required erecting configuration and maintain stable at the required erecting configuration. Besides, based on the basin of attraction of different stable configurations, the configuration triggering criteria of the bio-inspired erecting structure is studied, and the configuration triggering criteria composed of the excitation variables and configuration variables is revealed, which provide a theoretical basis for configuration switching of the bio-inspired erecting structure. The bio-inspired erecting structure proposed in this paper provide guidelines for function expansion of the earthworm-like robot. It is also a further improvement of the bionic design theory.