Active uncertainty reduction during gripping using range cameras-dual control

This paper is on sensor based control for guiding a robot to correct gripping of objects having a large position uncertainty. An eye-in-hand mounted range camera is considered. A probabilistic problem formulation based on the requested posture at gripping and corresponding tolerances is presented. The problem is solved approximately using dynamic programming for a 1-degree-of-freedom manipulator. A five-step dual control law is studied in more detail. A typical case is that in the first part of the control sequence the robot steers towards the optimal sensing position and in the last part the error with respect to the gripping posture is minimized. Since range camera sensing introduces both range dependent noise and occlusion there is a need for 'exploratory moves'. This behavior is formalized and includes 'dual control'.