Journal ArticleDOI
Qualitative analysis and quantitative evaluation of fixturing
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TLDR
In this paper, the necessary and sufficient condition for form-closure fixturing is derived and two quantitative indices, one to minimize the sum of all normal contact forces and the other to minimize maximum normal contact force, are presented.Abstract:
Form-closure is considered as a purely geometric property of a set of unilateral contact constraints such as those applied on a workpiece by a mechanical fixture. This paper provided qualitative analysis of form-closure fixturing. The necessary and sufficient condition for form-closure fixturing is derived. Some fundamental problems related to form-closure are solved such as minimum number of frictionless contact points and the way to arrange them to achieve form-closure. On the basis of qualitative analysis, the quantitative evaluation of form-closure is investigated. To assess quantitatively the form-closure fixturing, two quantitative indices, one to minimize the sum of all normal contact forces and the other to minimize the maximum normal contact force, are presented. Finally, the given example verifies the analysis method and evaluating indices.read more
Citations
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Journal ArticleDOI
A small displacement torsor model for tolerance analysis in a workpiece-fixture assembly
TL;DR: In this paper, the authors present a methodology for modelling and analysing the combined effect of these errors on a machined feature, expressed in terms of the small displacement torsor parameters.
Journal ArticleDOI
On Clamping Planning in Workpiece-Fixture Systems
TL;DR: A set of "compatibility" equations that describe the relationship between the displacement of the workpiece and the deformations at contacts and a locally elastic contact model to characterize the nonlinear coupling between the contact force and elastic deformation at the individual contact are derived.
Journal ArticleDOI
Geometric variation prediction in automotive assembling
TL;DR: In this paper, the authors developed a statistical error analysis model for assembling, to derive measures of controlling the geometric variations in assembly with multiple assembly stations, and to provide a statistical tolerance prediction/distribution toolkit integrated with CAD system for responding quickly to market opportunities with reduced manufacturing costs and improved quality.
Journal ArticleDOI
A geometric approach to automated fixture layout design
Yu Zheng,Chee-Meng Chew +1 more
TL;DR: This paper presents a method for finding form-closure locations of 4/7 fixels with enhanced immobilization capability and determines an optimal fixture layout very efficiently, so that it can be tried with various initial conditions to attain a result approaching the global optimum or with other good performance qualities.
Journal ArticleDOI
A unified framework of error evaluation and adjustment in machining
TL;DR: In this paper, the authors provide a framework for abstracting an error model that integrates three types of errors, i.e., machine tool, fixture, and datum errors, into a unified one.
References
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Journal ArticleDOI
Articulated Hands: Force Control and Kinematic Issues
J. Kenneth Salisbury,J. J. Craig +1 more
TL;DR: Several architectures for position and force control of this multiloop mechanism are described, including a way of dealing with the internal forces inherent in such systems.
Journal ArticleDOI
On the closure properties of robotic grasping
TL;DR: This article proves the equiva lence of force-closure analysis with the study of the equilibria of an ordinary differential equation, to which Lyapunov's di rect method is applied, and proposes an efficient algorithm for assessing the force- closure property of the grasp.
Book
Differential and Riemannian Manifolds
TL;DR: In this article, the authors provide an introduction to basic concepts in differential topology, differential geometry and differential equations, including vector fields and their integral curves, singular points, stable and unstable manifold, and the like.
Journal ArticleDOI
The Geometry of grasping
TL;DR: It is shown that form closure of any two-dimensional bounded object with piecewise smooth boundary (except a circle) can be achieved by four fingers, and it is proved that three fingers are necessary and sufficient in two dimensions, and four fingers in three dimensions.
Journal ArticleDOI
Kinematic analysis of workpart fixturing for flexible assembly with automatically reconfigurable fixtures
H. Harry Asada,A. By +1 more
TL;DR: In this article, the basic concept of an adaptable fixturing system and its hardware implementation are described, and the condition for a fixture layout to locate a given workpart uniquely at a desired location is derived.
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