Switching controller for efficient IBVS

Image-based visual servoing (IBVS) is now recognized to be an efficient and robust control strategy to guide robots using only visual data. Classical IBVS is commonly based on the Cartesian coordinates of points in the image. Although the convergence of the visual features to the desired ones is generally achieved, classical IBVS can lead to unnecessary displacements of the camera, such as the camera retreat problem in the case of a pure rotation around the optical axis. In contrast, IBVS based on the polar coordinates of points, is well adapted to carry out rotations around the optical axis but less adapted to manage translations. To take advantage of the benefits of each approach, we propose a new strategy for visual servoing based on a switching controller. The controller switches between Cartesian-based and polar-based approaches thanks to a switching signal provided by a decision maker. With the proposed controller, unnecessary 3D displacements are minimized without any 3D reconstruction and visibility constraints can be taken into account. The local stability of the closed-loop switching system is proved. A comparison with classical controllers and advanced controllers is performed by simulations. This comparative study illustrates the effectiveness of the proposed controller in terms of displacement in the image space and in the 3D space.