We propose an efficient kinematic position control for the center of mass of an articulated arm. The algorithm integrates the context of multiple joints reaching their limit value together with a singular configuration on the remaining joint space. We demonstrate the resulting fine control by interactively outlining the reachable area borders of the center of mass (in a 2D context for clarity). Moreover, the identification is also possible under any position or orientation constraint of an end effector. This tool can easily be integrated in the early conception stage of mobile articulated structures combining strong requirements on reachability and balance