Modeling and sliding mode control of a snake-like robot with holonomic constraints

In this paper modeling and robust sliding mode control of a snake-like robot in tracking of serpenoidal motion is addressed. By considering holonomic constraints, the kinematic and dynamic equations of a hyper redundant robot are obtained using Kane´s method. The Coulomb friction between robot´s wheels and the ground is modeled in two perpendicular directions (i.e. tangential and normal directions) with unknown coefficients of friction in each direction. A sliding manifold is defined by using position and velocity tracking errors of the relative motion between consecutive joints. Continuous approximation of switching control laws is used to eliminate chattering phenomena. The simulation results demonstrate that the snake-like robot realizes the trajectory tracking with desired robustness to the parameter uncertainties.