Solving Redundant Contact and Grasp Uncertainties

This paper extends previous work on (suboptimal) Kalman filter based resolution of geometric uncertainties that occur during the manipulation of an object in contact with its environment. The setup consists of a force-controlled robot which has grasped a cylindrical peg; the relative position and orientation of the peg with respect to the robot end effector are only approximately known. The peg is moved over a surface, whose position and orientation are also uncertain. This paper describes a general integrated task planning and force/velocity sensing approach that estimates the above-mentioned uncertainties, even if some of the geometric uncertainties are redundant, i.e., their influences on the force and/or velocity errors are instantaneously indistinguishable. The peg follows a smooth curve that gives sufficient excitation for the uncertainty parameter identification. Currently, the large number of calculations prohibits real-time implementation.