Spatial, bimanual, whole-arm grasping

We address the problem of synthesizing spatial, bimanual, whole-arm grasps by developing the abstractions of an open chain gripper, an open, spatial chain of rigid links and joints between the links, contacting a polyhedral object, and a generalized contact. We show that every general polyhedron can be immobilized by three generalized contacts. We leverage previous work on immobilization to construct an algorithm that synthesizes contact configurations for stable grasping. Our methodology can be applied to grasp a wide range of objects without relying on special-purpose end-effectors as shown in simulations and experiments with a PR2 humanoid robot.