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Planning Form-Closure Grasps of 2D Objects for
Robotic Hands

Research Authors
Khaled M. Shaaban and Hesham A. Mohamed
Research Department
Research Year
2012
Research Journal
Journal of Engineering Sciences
Research Publisher
Faculty of Engineering, Assiut University, Assiut, Egypt
Research Vol
Vol. 40 - No 6
Research Rank
2
Research_Pages
PP. 1759 -1780
Research Abstract

Grasp planning is the problem of finding the contact locations and the forces to apply by the fingers on the object surface to grasp it. This work proposes a new technique that solves a simplified version, (2-D), of this planning problem. This technique is used for planning form-closure grasps. In this type of grasp, the fingers surround the object and hold it securely against the palm. It could be used successfully to restrain the object with minimum concern about the applied forces even when the coefficient of friction is small. Instead of using shape primitives or hand preshapes to simplify the problem solution, this work suggests an optimization technique. This technique searches for the maximum value of a Grasp Quality Metric ( ) which corresponds to the best form-closure grasp. To find this value, the proposed technique requires the development of two algorithms. The first one generates a grasp for a given object at a specific approach angle of the robotic hand, and it is called the Grasp Generator. The second one is called the Search Algorithm. This algorithm explores all approach angles for the best grasp. The outputs of this algorithm are the position and the orientation of the palm and the joint angles of the fingers at the best grasp. The proposed method is used for a two-fingered robotic hand with eight degrees of freedom, and it is implemented and tested on a wide variety of 2D objects. The results show the effectiveness of the method to achieve the planning of form-closure grasps of any 2D object.