Sliding Mode Control of a Mobile Robot for Dynamic Obstacle Avoidance Based on a Time-Varying Harmonic Potential Field

In this paper, a harmonic potential field method for dynamic environments is proposed to generate an on-line reference trajectory for a wheeled mobile robot. A sliding mode controller is used to make the robot move along the prescribed trajectory determined by the gradient lines. The potential field is modified on-line, in order to make the robot avoid the collision with obstacles which move along non a-priori known trajectories with time-varying speed. The mechanism through which the field is modified is based on the so-called ‘collision cone’ concept.