Modeling and rolling gaits of a strut-actuated 6-strut locomotive tensegrity robot with membranes

Abstract

Tensegrity robots contain compression struts and tension tendons, allowing them to change their shape by controlling the lengths of members. Due to their excellent locomotion ability, they can play well when exploring complex environments. To protect the internal devices and meanwhile provide a base layer for thin film solar cells, membranes are proposed to cover the outer surface of the locomotive tensegrity in this study. A mathematical model for locomotive tensegrity with membranes is developed. A genetic algorithm incorporated with an incremental dynamic relaxation method is used to generate rolling gaits for the locomotive tensegrity with membranes. A classical strut-actuated 6-strut tensegrity system is taken as the basic model, and eight triangular membranes are covered on its outer surface to build a typical locomotive tensegrity with membranes. The influence of the membranes on the original rolling gaits generated by a numerical model of the 6-strut locomotive tensegrity without membranes is investigated. It is found that the effect of membranes becomes negligible when the relative stiffness between membranes and tendons is equal to or less than 1.2. When the effect of membranes is not negligible, the rolling gaits of the 6-strut locomotive tensegrity with membranes should be redesigned by using a numerical model taking the membranes into account. A physical prototype for the strut-actuated 6-strut locomotive tensegrity with membranes is fabricated, and tested to verify the feasibility of the redesigned rolling gaits.