The virtual linkage: a model for internal forces in multi-grasp manipulation

A model for characterizing internal forces and moments during multigrasp manipulation is proposed. The approach is based on construction of a physical model, called the virtual linkage, which is a closed-chain mechanism that represents the object being manipulated. Forces and moments applied at the grasp points of this linkage cause joint forces and torques at its actuators. When these actuators are subjected to the opposing forces and torques, the virtual linkage becomes a locked structure. Internal forces in the object are then characterized by these forces and torques. This approach was used in a multiarm robot system to manipulate objects while performing accurate control of internal forces