Force Closure Determination Algorithm for Parallel-Jaw Gripper

Key skills:

Force Closure / Grasp Wrench Space / Linear Programming

Abstract

This project is a toy project to understand the mechanism of force closure and how linear programming can be applied to determine analytic force closure of the given grasp. We referred the linear programming approach for force closure determination from the paper of Liu [1]. The corresponding code can be accessed through this link.

Method

The algorithm utilizes the duality of convex hull and convex polytope. In general, we deem the grasp is force closure when the convex hull of the grasp wrenches include the origin. In this regard, we can convert this determination problem to a ray shooting problem of convex hull through linear programming of vertices in the corresponding convex polytope.

Code Description

With the given example mesh (a nut), the program samples the potential contact points from the mesh. Then the model determines force closure of each grasp, which is a pair of potential contact points.

Seminar Material

I made a video clip for explaining about application of linear programming to force closure determination.

Currently, it is in Korean, but will add the English version in near future

References

[1] Liu, Y. H. (1999). Qualitative test and force optimization of 3-D frictional form-closure grasps using linear programming. IEEE Transactions on Robotics and Automation, 15(1), 163-173.