Study and resolution of singularities for a 7-DOF redundant manipulator

The singularity problem of a 7-DOF redundant manipulator is analyzed and resolved in this paper. To begin with, the singularities are decoupled into the position singularities and the orientation singularity by the technique of work space decomposition. Then, all the singular conditions for both the position singularities and the orientation singularity are derived. Finally, the new singularity avoidance (NSA) method is proposed to resolve the escapable singularities, which can be reconfigured into a nonsingular posture via self motion. Three examples are given to demonstrate the generality and efficiency of the NSA method