Robust 2.5D Visual Servoing for Robot Manipulators

In this paper, the 3-dimensional (3D) position and orientation of a camera held by the end-effector of a robot manipulator is regulated to a constant desired position and orientation despite (i) the lack of depth information of the actual or desired camera position from a target, (ii) the lack of a geometric model of the target object, and (iii) uncertainty regarding both the angle and axis of rotation of the camera with respect to the robot end-effector (i.e., the orientation extrinsic camera parameters). By fusing 2D image-space and projected 3D task-space information (i.e., 2.5D visual servoing), a robust controller is developed that ensures exponential regulation of the position and orientation of the camera. The stability of the controller is proven through a Lyapunov-based analysis.