A real-time approach for singularity avoidance in resolved motion rate control of robotic manipulators

In autonomous system, it is important to establish a control scheme that works with stability even near singularity configurations. In this article, we describe an on-line trajectory control scheme that uses the manipulability measure as a distance criteria to avoid manipulator singularities. The proposed approach consists in a method for limiting the minimum value of the distance criteria. The performance is simply affected by the choice of the lower limit. Based on a real-time evaluation of the measure of manipulability, this method does not require a preliminary knowledge of the singular configurations. The proposed algorithm is validated by experimental results.