Automatic Determination of Tolerance Chains in Unidirectional Tolerancing

2000 ◽  
Author(s):  
Charles Forster ◽  
Jean-Paul Boufflet ◽  
Fabien Lecouvreur
Keyword(s):  
Graph Theory ◽  
Functional Constraint ◽  
Second Step ◽  
Automatic Method ◽  
Functional Constraints ◽  
Mechanical Assembly ◽  
Automatic Determination ◽  
Cad System ◽  
Proposed Model

Abstract Herein is proposed an automatic method by which the all-tolerance chains of a mechanical assembly may be constructed. The method, implementable in a CAD system, is divided into two main steps. In the first step, we model the mechanical assembly with a graph, of which the vertices represent the parts and the edges, the contact between the parts. By « sliding » the parts, we may determine all the configurations of the mechanical assembly. The proposed model, which uses classical algorithms of the graph theory, allows control of the coherence of the mechanical assembly. In the second step, we introduce an extended syntax by which the functional constraints may be decoded without ambiguity. Then, using the syntax and the model, we show how to construct the tolerance chain for each functional constraint.

Automatic Determination of the Small Displacements in a Mechanical Assembly of Two Parts

2001 ◽  
Author(s):  
Charles Forster ◽  
Emmanuel Doré
Keyword(s):  
Second Step ◽  
Small Displacement ◽  
Automatic Method ◽  
Mechanical Assembly ◽  
Automatic Determination ◽  
Small Displacement Torsor ◽  
Nominal Position

Abstract Herein is proposed an automatic method by which the precision of a joint realized by the mechanical assembly of two parts may be totally determined. This precision depends on the dimensional and geometrical defaults existing in the parts, and is materialized by additional small displacements of the parts superposed with the kinematics of the joint. In a first step, the parts are represented by their geometrical entities, and the possible contacts existing between these entities. By ≪ sliding ≫ the parts around their nominal position, i.e. by opening or closing contacts between surfaces, one defines a new configuration of the assembly. In a second step, we give the conditions that this new configuration must fulfill to be physically acceptable. No parasitical motion is accepted, it must be possible to compute the small displacement torsor between the two configurations. And finally, no geometrical interferences are tolerated between the parts. In a third step, we apply this method on a simple but instructive bidimensional example.

Automatic Determination of Transmission Powerflow Mechanizability Using Graph Theory

2007 ◽  
Author(s):  
Norman K. Bucknor
Keyword(s):  
Graph Theory ◽  
Process Design ◽  
Visual Inspection ◽  
Computer Code ◽  
Graph Processing ◽  
Data Sets ◽  
Automatic Determination ◽  
Design Data ◽  
Processing Algorithms

A methodology has been developed to automatically generate planetary geartrain topologies based on criteria such as the number of desired speed ratios and the number of torque transmitting mechanisms [1]. This paper describes an algorithm and computer code for automatically determining the mechanizability of the candidate geartrains. The mathematical description of each topology is interpreted as a graph, a collection of vertices and connecting edges, which can then be tested for planarity using graph-processing algorithms. A planar graph implies mechanizability. Using another algorithm based on graph theory, the computer code also detects and eliminates duplicate designs that may be hard to detect via visual inspection. The computer program significantly reduces the time needed to manually process design data sets by eliminating those design candidates that are infeasible.

On Automatic Determination of Movement Phases in Manual Transport During the Precision Grip

2000 ◽  
Vol 28 (1-2) ◽  
pp. 237-245 ◽  
Author(s):  
Nasser Hosseini ◽  
Blanka Hejdukova ◽  
Pall E. Ingvarsson ◽  
Bo Johnels ◽  
Torsten Olsson
Keyword(s):  
Precision Grip ◽  
Automatic Determination

Automatic Determination of Optimal FIB Operations for Improved Circuit Probing and Fast Reconfiguration

2000 ◽  
Author(s):  
Romain Desplats ◽  
Timothee Dargnies ◽  
Jean-Christophe Courrege ◽  
Philippe Perdu ◽  
Jean-Louis Noullet
Keyword(s):  
Integrated Circuit ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Semiconductor Devices ◽  
Front Side ◽  
Automatic Determination ◽  
Metal Line ◽  
New Approach ◽  
Metal Layers

Abstract Focused Ion Beam (FIB) tools are widely used for Integrated Circuit (IC) debug and repair. With the increasing density of recent semiconductor devices, FIB operations are increasingly challenged, requiring access through 4 or more metal layers to reach a metal line of interest. In some cases, accessibility from the front side, through these metal layers, is so limited that backside FIB operations appear to be the most appropriate approach. The questions to be resolved before starting frontside or backside FIB operations on a device are: 1. Is it do-able, are the metal lines accessible? 2. What is the optimal positioning (e.g. accessing a metal 2 line is much faster and easier than digging down to a metal 6 line)? (for the backside) 3. What risk, time and cost are involved in FIB operations? In this paper, we will present a new approach, which allows the FIB user or designer to calculate the optimal FIB operation for debug and IC repair. It automatically selects the fastest and easiest milling and deposition FIB operations.

Modeling of Dynamic Loads on the Polished Rod of Pumping Unit in Case of Mulfunction of Rod Pump Operating

2014 ◽  
Vol 10 ◽  
pp. 95-101
Author(s):  
A.S. Topolnikov
Keyword(s):  
Multiphase Flow ◽  
Satisfactory Agreement ◽  
Model Simulation ◽  
Theoretical Modeling ◽  
Dynamic Loads ◽  
Plunger Pump ◽  
Proposed Model ◽  
Pumping Unit ◽  
Polished Rod

The paper presents the results of theoretical modeling of joined movement of pump rods and plunger pump and multiphase flow in a well for determination of dynamic loads on the polished rod of pumping unit. The specificity of the proposed model is the possibility of taking into account for complications in rod pump operating, such as leakage in valve steam, presence of gas and emulsion, incorrect fitting of plunger inside the cylinder pump. The satisfactory agreement of results of the model simulation with filed measurements are obtained.

scholarly journals Modeling Population Spatial-Temporal Distribution Using Taxis Origin and Destination Data

2021 ◽  
Vol 13 (7) ◽  
pp. 3727
Author(s):  
Fatema Rahimi ◽  
Abolghasem Sadeghi-Niaraki ◽  
Mostafa Ghodousi ◽  
Soo-Mi Choi
Keyword(s):  
Regression Analysis ◽  
Mean Squared Error ◽  
Population Distribution ◽  
Temporal Distribution ◽  
Coefficient Of Determination ◽  
Temporal Modeling ◽  
Location Data ◽  
Time Period ◽  
Proposed Model

During dangerous circumstances, knowledge about population distribution is essential for urban infrastructure architecture, policy-making, and urban planning with the best Spatial-temporal resolution. The spatial-temporal modeling of the population distribution of the case study was investigated in the present study. In this regard, the number of generated trips and absorbed trips using the taxis pick-up and drop-off location data was calculated first, and the census population was then allocated to each neighborhood. Finally, the Spatial-temporal distribution of the population was calculated using the developed model. In order to evaluate the model, a regression analysis between the census population and the predicted population for the time period between 21:00 to 23:00 was used. Based on the calculation of the number of generated and the absorbed trips, it showed a different spatial distribution for different hours in one day. The spatial pattern of the population distribution during the day was different from the population distribution during the night. The coefficient of determination of the regression analysis for the model (R2) was 0.9998, and the mean squared error was 10.78. The regression analysis showed that the model works well for the nighttime population at the neighborhood level, so the proposed model will be suitable for the day time population.

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