VFO stabilization of a unicycle robot with bounded curvature of motion

Abstract

Parking a vehicle at a fixed configuration in the presence of motion curvature constraints is a well known problem of substantial practical meaning. It has been addressed in the robotic literature mostly in the context of planning an optimized path-to-goal or by computing open-loop controls for a vehicle. The paper presents a novel approach to the constrained set-point control for a mobile robot utilizing the Vector-Field-Orientation (VFO) feedback control law combined with controller-driven planning of at most three waypoint configurations. Thanks to specific properties of the VFO controller the method is mostly analytic, provides design flexibility for control optimization, and permits combination of both forward and backward motion of the robot. The concept is presented for the unicycle kinematics, which is a generic body-motion model of most popular mobile robot structures. Formal considerations presented in the paper have been validated by simulations.