Simple solution for visual servoing of camera-in-hand robots in the 3d Cartesian space

In this paper, the control problem, in a 3D cartesian space, of camera-in-hand robotic systems is considered. In this approach, a camera is mounted on the robot, 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 considered object, a sphere in our case, coincides with the center of the image, and its apparent radius is constant. We propose a simple image-based direct visual servo controller which requires the knowledge of the objects´ radius, but it does not need to use the inverse Jacobian matrix. The robotic and vision system are modelled for small variations around the operating point for position control. In these conditions, the stability of the whole system is balanced and the characteristics for steady-state response for object trajectory are obtained. Both simulation and experimental results, using an ASEA-IRB6 robot manipulator, are presented to illustrate the proposed controller´s performance.