On invariant configuration of a three-fingered grasp

When grasping an object using three ngered end-e ectors, a certain geometrical entity can be created based on the grasping points and a de nition of an auxiliary point. This geometric con guration is referred to as the invariant con guration of the three ngered grasp. This paper exploits the geometric properties of such con guration using screw theory and inner product spaces. The results are shown to present themselves as an elegant and e cient framework in calculating the friction forces between the ngers and the grasped object and/or in de ning the instantaneous motion of the nger-tips in accomplishing the desired motion of the grasped object.