Stable visual servoing of camera-in-hand robotic systems

In this paper, the control problem of camera-in-hand robotic systems is considered. In this approach, a camera is mounted on the robot, usually at the hand, which provides an image of objects located in the robot environment. The aim of this approach is to move the robot arm in such a way that the image of the objects attains the desired locations. We propose a simple image-based direct visual servo controller which requires knowledge of the objects' depths, but it does not need to use the inverse kinematics and the inverse Jacobian matrix. By invoking the Lyapunov direct method, we show that the overall closed-loop system is stable and, under mild conditions on the Jacobian, local asymptotic stability is guaranteed. Experiments with a two degrees-of-freedom direct-drive manipulator are presented to illustrate the controller's performance.