Controlling wheel less snake-like robot by considering the Coulomb elliptical friction model and utilizing the path of Serpenoid curve

This article sets to investigates and analyzes the snake-like robot by applying Lagrange method to establish the equations of motion. Based on equations of motion, the generalized coordinates are the absolute angles of bodies and center of mass of the snake robot. Friction force into the system is evaluated through the Coulomb model and the contact surface based on the rectangle shape. The elliptical friction model of Coulomb friction is considered; as this model allows more realistic result compared to viscous friction model. Although the robots relative angles are specified as a function of time, the robots equations of motion will be evaluated in a way that, the torque of actuators is not directly inserted into the equations, and the relative angles are the system inputs. Based on the serpenoid curve and parametric control through this curve, which influence the whole movement of the robot, the robot is controlled in such a way that it can travel the prescribed path. Accordingly, the robot can travel well through the prescribed curvilinear and or linear paths. By utilizing this method, the robot is navigated from a point outside the design path towards the defined path.