Calculating hand configurations for precision and pinch grasps

Usually, grasp planning can be split up into two phases: In the first phase one tries to find a set of contacts that allow for stable grasping of an object. This phase has been of major research interest, which is also reflected in the (reasonable) definition of a grasp as a set of contact points. In the second phase a feasible hand pose that realizes the grasp with a given hand is calculated. While this point is important for a practical grasp planning system, it has either been considered trivial or been solved by crude heuristics in most cases. Here we present an approach for calculating the hand and finger pose for a given grasp. The problem is formulated as a constraint satisfaction problem and then solved using optimization techniques. The method is applied to two different grasp types: To the well known precision grasp and to the pinch grasp which is the grasp type preferred by men when grasping small objects.