Motion Analysis of a Snake-Like Robot in a Horizontal Surface, Considering the Coulomb Elliptical Friction Model and Utilizing the Path of Serpenoid Curve

This article investigates and analyzes the snake-like robot by applying Lagrange method to establish the equations of motion. Based on these equations, the generalized coordinates are the absolute angles of bodies and center of mass of the snake robot. The friction force was considered as the Coulomb model and the contacting surface was based on the rectangle shape. This model allows more realistic result compared to viscous friction model. Although the robot's relative angles are specified as functions of time, the robot's equations of motion were derived such that the torque of actuators were not directly inserted into the equations and the relative angles were the system's input. Based on the serpenoid curve and parametric control through this curve (which influences the whole movement of the robot), the robot will be controlled in such a way that it can travel in a prescribed path. Accordingly, the robot could travel well through the prescribed curvilinear and linear paths. By utilizing this method, the robot was navigated from a point outside the design path towards it.