On computing two-finger force-closure grasps of curved 2D objects

An approach to the computation of stable grasps of curved two-dimensional objects is presented. The authors consider the case of a hand equipped with two hard fingers and assume point contact with friction. Objects are modeled by parametric curves, and force-closure grasps are characterized by systems of polynomial constraints in the parameters of these curves. All configuration space regions satisfying these constraints are found by a numerical cell decomposition algorithm based on curve tracing and continuation techniques. Maximal object segments where fingers can be positioned independently are found by optimization within the grasp regions. The approach has been implemented and examples are presented