Tolerance Analysis With Polytopes in HV-Description

2017 ◽  
Vol 17 (4) ◽  
Author(s):  
Santiago Arroyave-Tobón ◽  
Denis Teissandier ◽  
Vincent Delos
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
Dual Space ◽  
Tolerance Analysis ◽  
Minkowski Sum ◽  
Duality Property ◽  
Finite Set ◽  
Minkowski Sums

This article proposes the use of polytopes in HV-description to solve tolerance analysis problems. Polytopes are defined by a finite set of half-spaces representing geometric, contact, or functional specifications. However, the list of the vertices of the polytopes is useful for computing other operations as Minkowski sums. Then, this paper proposes a truncation algorithm to obtain the V-description of polytopes in ℝn from its H-description. It is detailed how intersections of polytopes can be calculated by means of the truncation algorithm. Minkowski sums as well can be computed using this algorithm making use of the duality property of polytopes. Therefore, a Minkowski sum can be calculated intersecting some half-spaces in the dual space. Finally, the approach based on HV-polytopes is illustrated by the tolerance analysis of a real industrial case using the open source software politocat and politopix.

Tolerance Analysis With Polytopes in HV-Description

2016 ◽  
Author(s):  
Santiago Arroyave-Tobón ◽  
Denis Teissandier ◽  
Vincent Delos
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
Dual Space ◽  
Tolerance Analysis ◽  
Minkowski Sum ◽  
Duality Property ◽  
Finite Set ◽  
Minkowski Sums

This article proposes the use of polytopes in HV-description to solve tolerance analysis problems. Polytopes are defined by a finite set of half-spaces representing geometric, contact or functional specifications. However, the list of the vertices of the poly-topes are useful for computing other operations as Minkowski sums. Then, this paper proposes a truncation algorithm to obtain the V-description of polytopes in ℝn from its H-description. It is detailed how intersections of polytopes can be calculated by means of the truncation algorithm. Minkowski sums as well can be computed using this algorithm making use of the duality property of polytopes. Therefore, a Minkowski sum can be calculated intersecting some half-spaces in the dual space. Finally, the approach based on HV-polytopes is illustrated by the tolerance analysis of a real industrial case using the open source software PolitoCAT and politopix.

Form Defects Consideration in Polytope-Based Tolerance Analysis

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Ting Liu ◽  
Laurent Pierre ◽  
Nabil Anwer ◽  
Yanlong Cao ◽  
Jiangxin Yang
Keyword(s):  
Tolerance Analysis ◽  
Significant Loss ◽  
Minkowski Sum ◽  
Skin Model ◽  
Model Combining ◽  
Perfect Form ◽  
Finite Set ◽  
Physical Shape ◽  
Polytope Model

The polytope-based tolerance analysis in design process uses a finite set of constraints to represent specifications and propagates these constraints to any objective point in the Euclidean space. The operations of Minkowski sum and intersection on polytopes are well suited to serial and parallel assemblies. The polytope model has been applied to complex assemblies which contain a large number of joints and geometrical tolerances. However, the previous studies on this model consider toleranced features as surfaces of perfect form. The ignorance of form defects in tolerance analysis would result in a significant loss in accuracy and reliability. In this paper, an extension of the polytope model for tolerance analysis considering form defects is described in which the skin model shape representing the physical shape of the product is adopted to simulate the actual toleranced feature in place of the substitute one used conventionally. The combination of polytope model and skin model shape is expected to inherit many of the advantages of each model, combining easy-to-use tolerance propagation and form defects representation with accuracy guarantees. To demonstrate the method and its respective application, a case study of an assembly is illustrated in detail. The proposed method further enhances the capability of the polytope model in handling form defects and provides more realistic assembly results that approximate the actual assembly conditions for design evaluation.

An Algorithm for Gradual Patch Acceptance Detection in Open Source Software Repository Mining

2012 ◽  
Vol E95.A (9) ◽  
pp. 1478-1489
Author(s):  
Passakorn PHANNACHITTA ◽  
Akinori IHARA ◽  
Pijak JIRAPIWONG ◽  
Masao OHIRA ◽  
Ken-ichi MATSUMOTO
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
Software Repository ◽  
Repository Mining ◽  
Software Repository Mining

Hacking Diversity

2019 ◽  
Author(s):  
Christina Dunbar-Hester
Keyword(s):  
Open Source ◽  
Human Resource ◽  
Open Source Software ◽  
Cultural Production ◽  
Equal Opportunity ◽  
Economic Power ◽  
Underrepresented Groups ◽  
Technical Production ◽  
Preferred Solutions

Hacking, as a mode of technical and cultural production, is commonly celebrated for its extraordinary freedoms of creation and circulation. Yet surprisingly few women participate in it: rates of involvement by technologically skilled women are drastically lower in hacking communities than in industry and academia. This book investigates the activists engaged in free and open-source software to understand why, despite their efforts, they fail to achieve the diversity that their ideals support. The book shows that within this well-meaning volunteer world, beyond the sway of human resource departments and equal opportunity legislation, members of underrepresented groups face unique challenges. The book explores who participates in voluntaristic technology cultures, to what ends, and with what consequences. Digging deep into the fundamental assumptions underpinning STEM-oriented societies, the book demonstrates that while the preferred solutions of tech enthusiasts—their “hacks” of projects and cultures—can ameliorate some of the “bugs” within their own communities, these methods come up short for issues of unequal social and economic power. Distributing “diversity” in technical production is not equal to generating justice. The book reframes questions of diversity advocacy to consider what interventions might appropriately broaden inclusion and participation in the hacking world and beyond.

Web Based GIS Application using Open Source Software for Sharing Geospatial Data

2015 ◽  
Vol 4 (1) ◽  
pp. 1224-1228 ◽  
Author(s):  
Debasish Chakraborty ◽  
◽  
Debanjan Sarkar ◽  
Shubham Agarwal ◽  
Dibyendu Dutta ◽  
...  
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
Geospatial Data ◽  
Web Based ◽  
Gis Application
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