Wrench Closure: the property of an arrangement of contacts, usually from a robotic hand or a fixturing device, that guarantees that the contact system can reject disturbance forces on the object (up to limitations in the manipulator). Wrench closure asserts that there exists a set of contact forces and moments that surrounds and contains the origin in the six dimensional wrench space. The analysis involves estimating the set of forces that can be transmitted by contacts and can include frictional forces in the contact model.y