Combining geometric and physical models: the case of a dextrous hand

Planning robust grasping operations involving a dextrous robotics hand and an object located in a 3D workspace requires the combination of two main types of techniques: a geometric based reasoning aimed at producing a grasping strategy; and a physical analysis of the object/hand interactions. The second type of technique is clearly necessary to conclude on the feasibility of the chosen grasping strategy (stability in particular) and to determine the type of control to apply onto the hand. The purpose of this paper is to propose a technique based upon the concept of “physical models” for solving this problem. We show how physical models can be constructed and used to solve the associated stability and control strategy problems. We also show how the related techniques can be combined with more classical geometric methods to solve the whole problem. We describe the modeling of the task, the connection between geometric and physical constructions, the characteristics of the motion planning process, and the experimental results which have been obtained