Image-based and intrinsic-free visual navigation of a mobile robot defined as a global visual servoing task

The new contribution of this paper is the definition of the visual navigation as a global visual control task which implies continuity problems produced by the changes of visibility of image features during the navigation. A new smooth task function is proposed and a continuous control law is obtained by imposing the exponential decrease of this task function to zero. Finally, the visual servoing techniques used to carry out the navigation are the image-based and the intrinsic-free approaches. Both are independent of calibration errors which is very useful since it is so difficult to get a good calibration in this kind of systems. Also, the second technique allows us to control the camera in spite of the variation of its intrinsic parameters. So, it is possible to modify the zoom of the camera, for instance to get more details, and drive the camera to its reference position at the same time. An exhaustive number of experiments using virtual reality worlds to simulate a typical indoor environment have been carried out.