Modeling and Control of a Cable Driven Modular Snake Robot

This paper presents the modeling and control of a planar snake robot composed of modular, single degree of freedom bending units. The goal of this research is to design a snake robot that minimizes the number of degrees of freedom necessary for planar serpentine locomotion, while closely approximating the idealized sinusoidal shape of a moving snake. The use of an underactuated, multi-link module as the snake's basic functional unit aims at simplifying the control of snake robots while retaining the advantages of highly articulated designs. The design and dynamic model of the snake robot are presented, and a controller is developed that demonstrates path following between waypoints and disturbance rejection, under viscous and Coulomb frictional models. Controller design for the reduced-DOF snake is presented and related to the control of snake robots that independently actuate all of their joints. Key control and design parameters are then optimized to produce curvature profiles that maximize the robot's forward speed.