The condition for contact grasp stability

Abstract

We distinguish between two types of grasp stability, which we call spatial grasp stability and contact grasp stability. The former is the tendency of the grasped object t o return to an equilibrium location in space; the latter is the tendency of the points of contact to return to an equilibrium position on the object's surface. We show via examples that spatial stability cannot capture certain intuitive concepts of grasp stability and hence that any full understanding of grasp stability must include contact stability. We derive a model of how the positions of the points of contact evolve in time on the surface of the grasped object in the absence of any external force or active feedback. From this model, we obtain a condition which determines whether or not a two-fingered grasp is contact stable.

An overview of 3D object grasp synthesis algorithms

“…There is a wide disparity in the terminology used in the grasping literature regarding equilibrium, stability, force closure and form closure terms [2][3][4][5][6][7]. We adopt the terminology used in [4] and summarize in the following the corresponding definitions.…”

“…They are reflected by properties such as form-closure, force-closure and more generally by the ''contact stability'' [2][3][4][5][6][7].…”

Learning of 2D grasping strategies from box-based 3D object approximations

“…The fact that studies have shown that slightly concave curvature may be better suited [15] is left as a possible extension to the work. For this task a combination of the Canny edge detector and the k-angular bending algorithm [16] was used.…”

Using Experience for Assessing Grasp Reliability

“…A concave surface is a better place to put a finger for grasping purposes than a convex one [12]. This feature takes into account the curvature of the three grasp zones.…”