Bounded Self-motion of Functional Redundant Robots

Abstract

In this paper, we consider a problem how to exploit a task space motion for lower-priority tasks when the end-effector motion allows some deviation of the motion for the primary task. Using a common redundancy resolution methods, the self-motion is only possible in the null-space. Therefore, we propose a novel combination of controllers in two spaces: in the task space and in the reduced task space, where DOFs corresponding to spatial directions allowing the deviations are excluded. The motion generated by the controller in the reduced task space is mapped into the main task and by properly selecting the controller parameters the resulting motion does not violate the constraints. To demonstrate the effectiveness of the proposed control we show simulation examples where motion in a constraint region is used to avoid joint limits.