Use of first derivative of geometric features in visual servoing

Visual servoing is based on an array of measurements taken from a set of images and used each time as an error function to compute a control vector. This is applied to the system (robot and camera) and makes it move in order to reach a desired situation, at the end of the task, directly depicted in the image. The originality of this recent work consists in improving the visual servoing approach. To do this, we consider a signal sensor vector constructed of a geometrical feature ((x,y) point coordinates, line parameters, etc.) and its first derivative. In this paper, we show how to work out the interaction matrix. We have tested this new approach on a workstation in the case of the point feature. We have also implemented it on our robotic platform. The overall results show a great improvement due to the action of this new signal sensor. We are extending this approach to more complex features.