In this paper we discuss the relation between the two approaches to velocity command generation for nonredundant robotic mechanisms, which the two groups of the authors proposed recently and independently of each other. It will be shown analytically that the singularity-consistent null space based approach, and the split Jacobian approach, are equivalent. Analysis of the behavior at a singularity will be presented from the viewpoint of both approaches. An analytical example will be used to demonstrate the theoretical results.

This paper presents a novel approach to singularity treatment of non-redundant robots. In particular it tries to yield a complete solution to the singularity problem. Based on the symbolic deduction of the inverse Jacobian a necessary condition is derived to discriminate between executable and non-executable motions. In this context the redundant motions in a singular robot configuration are examined and illustrated. The robot can move out of the singular configuration without any position or orientation error. Two strategies are derived to move through the singular configuration. The results although general-are verified using the six axis ROTEX robot, the first remotely controlled space robot.