Robust visual servoing based on relative orientation

In this paper the problem of controlling the spatial position and orientation of a robotic platform based on the image data obtained from a video camera mounted on that platform is considered. More specifically, we propose control laws that generate translational and angular velocities that will cause the robot to achieve and maintain a fixed position and orientation with respect to a set of feature points in the scene. The proposed control schemes make use of well established techniques for computing estimates for the relative orientation of two camera positions from a set of feature correspondences. An important advantage of these control schemes is that it is possible to demonstrate analytically that they are globally convergent even in the presence of large calibration errors in both the intrinsic parameters of the camera and in the extrinsic parameters which relate the frame of reference of the camera to the body frame of the robot platform which is being controlled. Furthermore no a priori knowledge about the structure of the scene is assumed.