Grasping polyhedral objects with slip

A force strategy developed by R.S. Fearing (1986) for automatically grasping two-dimensional polygon objects by a dextrous hand with point contact with friction is shown to be applicable to three-dimensional polyhedral objects. The algorithm essentially consists of position control of one finger and force control of the other along the internal force directions. Basic geometric constraints on the object are obtained for feasible grasping with two fingers. It is observed that, when an object is rotated about the line passing through soft finger contacts, the fingers slip on the object in a simple predictable trajectory