Estimation of Mass and Center of Gravity of Graspless Unknown Object Based on Gravity Equi-Effect Planes.

摘要

For manipulating an object stably and accurately by robot, it is frequently required to know the mass and center of gravity of the object. For the case when the weight and/or shape of an object is over the grasp capacity of a robot hand, this paper proposes a technique that can estimate the center of gravity and mass of the graspless and shapeunknown object. A plane called Gravity Equi-Effect Plane is introduced, which contains the center of gravity and a contact line where the object is in line-contact with an environment. If three or more gravity equi-effect planes, which correspond to different contact lines of an object, are obtained, the center of gravity of the object can be determined by the intersect point of these planes. In order to estimate the gravity equi-effect plane, Tip Operation with robot finger, which tips the object several times, is proposed. Then, algorithms to estimate the gravity equi-effect plane and to determine the mass and center of gravity of the object are given by fusing the fingertip position and force information measured from tip operations. Lastly, experimental verification on the proposed approach is performed.