Sensing Object Location with Dextrous Hand

Manipulating objects with a dextrous hand often requires knowledge about the location of objects relative to the hand. The paper describes a canonical configuration approach to sensing locations of polyhedral objects by active touch. The idea is to let the hand explore the object with its multiple fingers and the attached sensors. The sensory data derived from external tactile sensors, internal force and position sensors are in the form of lines. This is done by controlling the finger tips to move straight on the surface of the object, or by actuating the fingers to have line contacts with the object. By transforming the lines into the canonical configuration, the relative orientation between the object and the hand can be easily found by solving the zeros of a polynomial of degree 8. Sensing strategies for avoiding degenerate line-face configurations which lead to infinite number of solutions are presented. Different examples for illustrating the approach are also described.