Grasp Database That Covers Variation of Contact Region Usage

Abstract

This paper proposes a novel approach to build a human grasp database that considers contact regions for grasping posture synthesis. To cover all types of hand surface regions contacting an object when grasping, the grasp taxonomy from other research was extended. For each pattern of region usage, we collected several posture variations that differ in the distance between regions. In total, 801 postures were collected for 107 patterns of region usage. A posture to grasp a new object was generated by interpolation with optimization-based adjustment using the proposed database, given a goal contact state of the hand with the object.

Grasp Synthesis for Digital Hands with Limited Range of Motion in Their Thumb Joints

“…Since individual differences among ROMs are very large even in healthy [22] hands, only the rough features of the measured limited ROM in [21] were considered in the ROM limitation for the grasp synthesis in this paper. In the coordinate system of the hand model used by [10] and [11], it was confirmed that the ROM limitation by the taping method proposed in [21] restricted about 60% of the palmar abduction and 40% of the radial abduction.…”

“…In this paper, the method of grasp synthesis for healthy hands proposed in [10] and [11] is applied to grasp synthesis for ROM-limited hands. This section explains an overview of the algorithm of grasp synthesis.…”

“…The greatest feature of this method is the use of grasp database based on the "contact regions." The outline of the method of grasp synthesis proposed in [10] and [11] is shown in Fig. 1.…”

“…1. Outline of the method of grasp synthesis proposed in [10] and [11] interference avoidance is considered to ensure the avoidance of interference among the fingers or the palm. The hand model is divided into 18 rigid bodies and the interference is checked for all pairs of segments using proximity query package [20].…”

“…This paper aims to synthesize the grasps for thumb's ROM-limited hands by adding the information of the ROM limitation to the database of healthy hands proposed by [10] and [11]. As another approach, it is possible to create a new database for ROM-limited hands from scratch.…”