Active force closure for multiple objects

This article discusses active force closure (AFC) for the manipulation of multiple objects. AFC formultiple objects is defined in such a way that the finger can generate an arbitrary acceleration onto a certainpoint of multiple objects. We define two kinds of AFC: in the first, an arbitrary acceleration can be generatedonto each of the objects; in the second, an arbitrary acceleration can be generated onto the center of massof multiple objects without changing the relative position of the objects. We show that the grasped object cannotalways be manipulated arbitrarily even if the first kind of AFC is satisfied. We also show that the graspedobjects are manipulated like a single rigid body if the second kind of AFC is satisfied. To explain these featuresof AFCs, numerical examples for the grasp of three objects are shown. © 2002 Wiley Periodicals, Inc.