Highly precise micropositioning task using a direct visual servoing scheme

This paper demonstrates accurate micropositioning scheme based on a direct visual servoing process. This technique uses only the pure image signal (photometric information) to design the control law. With respect to traditional visual servoing approaches that use geometric visual features (points, lines ...), the visual features used in the control law are the pixel intensity. The proposed approach was tested in term of accuracy and robustness in several experimental conditions. The obtained results have demonstrated a good behavior of the control law and very good positioning accuracy. The obtained accuracies are estimated to 14 nm, 89 nm, and 0.001 degrees in the x, y and θ axes of positioning platform, respectively.