ON COMPUTING 2-FINGER FORCE-CLOSURE GRASPS OF CURVED 2D OBJECTS

This article presents an algorithm for computing force-closure grasps of piecewise-smooth, curved, two-dimensional objects. We consider the case of a gripper equipped with two hard fingers and assume point cont act with friction. Object boundaries are represented by collections of polynomial parametric curves, and force-closure grasps are characteri zed by systems of polynomial constraints in the parameters of these cu rves. All configuration space regions satisfying these constraints are found by a parallel numerical cell-decomposition algorithm based on c urve tracing and continuation techniques. Maximal curve segments where fingers can be positioned independently are found by optimization wit hin the grasp regions. The algorithm has been implemented on a distrib uted architecture, and experiments using a PUMA robot equipped with a pneumatic two-finger gripper and a vision system are presented.