Direct visual servoing of a redundant robot with chaos compensation

This paper presents a direct visual servoing system to control a redundant robot. To solve the redundancy the concepts of manipulability and perceptibility are combined in a priority based scheme. The proposed dynamic controller determines the appropriate motor references such that the robot-end and joints behave correctly. In order to guarantee the applicability of this approach, a repetitive path tracked by the robot-end must produce a periodic joint motion. The paper describes experiments in which a non-periodic joint motion is obtained during the tracking of repetitive image trajectories. To solve this problem, delayed feedback control is integrated in the dynamic controller in order to avoid chaotic behavior in the joint space during the tracking of these image trajectories. Furthermore, a method to adjust this last controller is proposed based on experimental results.