Simulating grasping behavior of people using the relational description scheme

Vipin, JS and Sen, Dibakar (2011) Simulating grasping behavior of people using the relational description scheme. In: First International Symposium on Digital Human Modeling (DHM2011), June 14-16, 2011, Lyon, France.

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Abstract

This paper presents an enhanced relational description for the prescription of the grasp requirement and evolution of the posture of a digital human hand towards satisfaction of this requirement. Precise relational description needs anatomical segmentation of the hand geometry into palmar, dorsal and lateral patches using the palm-plane and joint locations information, and operational segmentation of the object geometry into pull,push and lateral patches with due consideration to the effect of friction. Relational description identifies appropriate patches for a desired grasp condition. Satisfaction of this requirement occurs in two discrete stages,namely,contact establishment and post-contact force exertion for object capturing. Contact establishment occurs in four potentially overlapping phases,namely,re-orientation,transfer,pre- shaping,and closing-in. The novel h and re-orientation phase,enables the palm to face the object in a task sequence scenario, transfer takes the wrist to the ball park ; pre-shaping and close-in finally achieves the contact. In this paper, an anatomically pertinent closed-form formulation is presented for the closing-in phase for identification of the point of contact on the patches ,prescribed by the relational description. Since mere contact does not ensure grasp and slip phenomenon at the point of contact on application of force is a common occurrence, the effect of slip in presence of friction has been studied for 2D and 3D object grasping endeavours and a computational generation of the slip locus is presented.A general slip locus is found to be a non-linear curve even on planar faces.Two varieties of slip phenomena,namely,stabilizing and non-stabilizing slips, and their local characteristics have been identified.Study of the evolution of this slip characteristic over the slip locus exhibited diverse grasping behaviour possibilities. Thus, the relational description paradigm not only makes the requirement specification easy and meaningful but also enables high fidelity hand object interaction studies possible.

Item Type:	Conference Paper
Keywords:	Virtual Hand; Grasp Stability; Grasp Planning; Grasp Simulation; Slip Motion
Department/Centre:	Division of Mechanical Sciences > Centre for Product Design & Manufacturing
Date Deposited:	08 May 2013 06:05
Last Modified:	08 May 2013 06:05
URI:	http://eprints.iisc.ac.in/id/eprint/46347

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