A New Approach to Kinematics Modelling of Snake-Robot Concertina Locomotion

Abstract

In this paper, for the first time, kinematics<br><br>modelling of snake robot travelling with concertina locomotion<br><br>is presented. Next a novel kinematics modelling method is<br><br>presented which has an advantage of allowing natural snake<br><br>like locomotion. During concertina motion, certain parts of the<br><br>body contract, expand or do not change their shape. This<br><br>results into having different body curves for different parts of<br><br>a snake. To simulate this, first we introduce a mathematical<br><br>equation, called dynamic function, in which by varying a<br><br>certain function parameter, body curve during motion is<br><br>realized. To obtain concertina gait, the snake body is divided<br><br>into three different modules, head module, tail module and<br><br>main body module that connects the head to the tail module.<br><br>Each module forms a specific curve which can be modelled<br><br>using the proposed dynamic function. At each moment during<br><br>snake locomotion, the kinematics of different links can be<br><br>derived by fitting links to the body curve. Finally concertina<br><br>locomotion is simulated using Webots software. Results<br><br>indicate concertina locomotion can be obtained. Furthermore,<br><br>the proposed dynamic function requires relatively lower<br><br>computation requirement. Therefore, adaption of body curve<br><br>to other real snake like gaits as well as mixed type locomotion<br><br>is made possible. This works represents a first approach to a<br><br>simulation of a snake-like mechanism in order to get basic<br><br>characteristics of such locomotion and to enable our future<br><br>research.