Implementation of a homography-based visual servo control using a quaternion formulation

In this paper, we present the implementation of a homography-based visual servo controller as introduced in (Hu et al., 2006). In contrast to other visual servo controllers, this formulation uses a quaternion representation of the rotation. By doing so, potential singularities introduced by the rotational matrix representation can be avoided, which is usually a very desirable property in, for example, aerospace applications such as for visual control of satellites, helicopters, etc. The movement of the camera and the image processing were performed using a simulation of the real environment. This testing environment was developed in Matlab-Simulink and it allowed us to test the controller regardeless of the mechanism in which the camera was moved and the underlying controller that was needed for this movement. The final controller was tested using yet another simulation program provided by Kawasaki Japan for the UX 150 industrial robot. The setup for testing and the results of the simulations are presented in this paper.