The problem of boundary following by a unicycle-like robot with rigidly mounted sensors

We consider the problem of reactively navigating an unmanned Dubins-like robot along an equidistant curve of an environmental object based on the distance to its boundary measured perpendicularly to the robot centerline and the angle of incidence of this perpendicular to the boundary. Such a situation holds if e.g., the measurements are supplied by range sensors rigidly mounted to the vehicle body at nearly right angles, or by a single sensor scanning a nearly perpendicular narrow sector. A sliding mode control law is proposed that drives the robot at a pre-specified distance from the boundary and maintains this distance afterwards. This is achieved without estimation of the boundary curvature and holds for boundaries with both convexities and concavities. Mathematically rigorous analysis of the proposed control law is provided, including an explicit account for the global geometry of the boundary. Computer simulations and experiments with real wheeled robots confirm the applicability and performance of the proposed guidance approach.

► New boundary following approach for mobile wheeled robots. ► Boundary sensing limited to a single direction relative to the vehicle. ► Achievement of the control objective rigorously shown. ► Simulations and real world testing show the validity of the approach.