VFO controller for set-point visual servoing of unicycle-like mobile robots equipped with a camera of an uncertain depth scale factor

The paper presents derivation, control performance analysis, and numerical validation of the Vector Field Orientation (VFO) control law devised for visual servoing of the input-constrained unicycle-like robot equipped with an onboard camera of an uncertain depth scale factor. It is shown that an inherent robustness of the proposed VFO controller ensures exponential convergence of the robot pose error toward zero despite even large uncertainty of the depth scale factor. This property allows simplifying applications of visual servoing with the VFO controller by avoiding a precise calibration process relating the on-board camera and the reference plane of feature points. Simulation results show the effectiveness and robustness of the proposed approach.