Estimation of contact position between a grasped object and the environment based on sensor fusion of vision and force

Robots require various techniques of sensor fusion to achieve effectively manipulation tasks. This paper presents a sensor fusion method of vision and force information to estimate contact position between a grasped object and the other objects in the environment. The technique will be useful especially for assembly tasks since manipulation of an object by using visual information only often falls into difficulties because of the occlusions caused by the grasped object, surrounding objects, and the manipulator itself. In such situations, force sensor information helps to estimate the contact position even when the exact contact position is invisible. Consequently, sensor fusion of vision and force permits to improve adaptability of robot systems to changing situations in the task. Experiments using a robot system demonstrate usefulness of the proposed method. In addition, we address problems of sensor planning to automatically select sensor information taking the fusion of vision and force into account.