Grasp Optimization Under Specific Contact Constraints

Abstract

Abstract-This paper presents a procedure to synthesize highquality grasps for objects that need to be held and manipulated in a specific way, characterized by a pre-specified set of contact constraints to be satisfied. Due to the multi-modal nature of typical grasp quality measures, approaches that resort to local optimization methods are likely to get trapped into local extrema on such problem. An additional difficulty of the problem is that the set of feasible grasps is a highly-dimensional manifold, implicitly defined by a system of non-linear equations. The proposed procedure finds a way around these issues by focusing the exploration on a relevant subset of grasps of lower dimension, and tracing this subset exhaustively using a higher-dimensional continuation technique. A detailed atlas of the subset is obtained as a result, on which the highest-quality grasp according to any desired criterion, or a combination of criteria, can be readily identified. Examples are included that illustrate the application of the method to a three-fingered planar hand and to the Schunk anthropomorphic hand grasping several objects, using several quality indices.

The CUIK Suite: Analyzing the Motion Closed-Chain Multibody Systems

“…In this case, the atlas construction takes 0.1 seconds on a standard desktop computer, while the isolation of the same space using branch-and-prune techniques Left: The configuration of the hand-object system must satisfy a number of contact constraints. An initial feasible grasp is computed using the branchand-prune methods [25] and is used as the initial configuration from which to construct an atlas of the relevant C-space subset [24]. Right: The chart centers of this atlas can be evaluated according to a performance criterion in order to select the optimal grasp.…”

An Open-Source Toolbox for Motion Analysis of Closed-Chain Mechanisms

“…Red polygons represent the charts to be extended in subsequent iterations. of a whole atlas is typically fast in 1-or 2-dimensional C-spaces, which allows tackling difficult optimization problems involving large multibody systems [19].…”

Distance Geometry in Active Structures

“…15) the configuration space becomes a null-measure manifold embedded in the ambient space formed by the joint variables [24]. Actually, kinematic loops appears in many relevant problems such as complex manipulation problems [51], parallel robot path generation [28], grasp planning [48], or surgery planning [2]. Fig.…”