The Set-Up-Map for Automating the Positioning of Castings and Weldments in Fixtures to Ensure Completely Machined Surfaces

2016 ◽  
Author(s):  
Nathan J. Kalish ◽  
Satchit Ramnath ◽  
Payam Haghighi ◽  
Joseph K. Davidson ◽  
Jami J. Shah ◽  
...  
Keyword(s):  
Dimensional Space ◽  
Small Body ◽  
Three Dimensional ◽  
Global Coordinate System ◽  
Tolerance Zone ◽  
Machined Surface ◽  
Cloud Data ◽  
Machining Fixtures ◽  
Set Up ◽  
Intersection Method

There is considerable geometric variability of raw castings and weldments before any machining of surfaces that assemble with other components. Consequently, considerable time often is spent identifying successful set-up adjustments at the machining fixtures for such parts in a way to ensure that every machined surface will be complete. The proposed Set-Up-Map© is a point-space subset of R6 where each of the six orthogonal coordinates correspond to one of the rigid-body displacements in three dimensional space: three translations and three rotations. Any point within the Set-Up-Map (S-Map) corresponds to a small body displacement (SBD) of the part that satisfies the condition that each feature will lie within its associated tolerance zone after machining. S-Maps are derived from previous work on Tolerance Maps© (T-Maps), which represent feature deviations allowed by a given tolerance zone. Each raw casting or weldment is scanned, and the point-cloud data fitted to individual features, to determine how much each to-be-machined (TBM) feature deviates from nominal specifications. Each local T-Map is formed from a library, then shifted to be centered on its corresponding scanned feature on each casting; it becomes a local S-Map primitive. Each of these local S-Maps is then transformed to a single global reference frame. The intersection of these S-Map primitives in the global frame gives the allowable small body displacements that satisfy the positioning requirements for all TBM features. Since T-Maps are convex objects, a half-space intersection method is used to generate an S-Map. Any point within the S-Map represents a viable small body displacement specific to the global coordinate system established on the part. In the case that as-cast or as-welded features deviate from what is acceptable, the S-Map will be the empty set. Consequently, in addition to reducing the time for setup in a fixture, S-Maps can serve as a valuable diagnostic to determine that a part should be either scrapped or reworked.

scholarly journals Three-Dimensional Synthesis of Manufacturing Tolerances Based on Analysis Using the Ascending Approach

Mathematics ◽  
2022 ◽  
Vol 10 (2) ◽  
pp. 203
Author(s):  
Badreddine Ayadi ◽  
Lotfi Ben Said ◽  
Mohamed Boujelbene ◽  
Sid Ali Betrouni
Keyword(s):  
Surface Defects ◽  
Three Dimensional ◽  
Tolerance Analysis ◽  
Machining Process ◽  
Dimensional Synthesis ◽  
Machining Processes ◽  
Machined Surface ◽  
Manufacturing Tolerances ◽  
Machining Fixtures ◽  
Set Up

The present paper develops a new approach for manufacturing tolerances synthesis to allow the distribution of these tolerances over the different phases concerned in machining processes using relationships written in the tolerance analysis phase that have been well developed in our previous works. The novelty of the proposed approach is that the treatment of non-conventional surfaces does not pose a particular problem, since the toleranced surface is discretized. Thus, it is possible to study the feasibility of a single critical requirement as an example. During the present approach, we only look for variables that influence the requirements and the others are noted F (Free). These variables can be perfectly identified on the machine, which can be applied for known and unknown machining fixtures; this can be the base for proposing a normalized ISO specification used in the different machining phases of a mechanical part. The synthesis of machining tolerances takes place in three steps: (1) Analysis of the relationship’s terms, which include the influence of three main defects; the deviation on the machined surface, defects in the machining set-up, and the influence of positioning dispersions; then (2) optimization of machining tolerance through a precise evaluation of these effects; and finally (3) the optimization of the precision of the workpiece fixture, which will give the dimensioning of the machining assembly for the tooling and will allow the machining assembly to be qualified. The approach used proved its efficiency in the end by presenting the optimal machining process drawing that explains the ordered phases needed to process the workpiece object of the case study.

Origin of the Nucleation Rate Empirical Data Inconsistencies for the Vapor-Gas Systems

2008 ◽  
Vol 3 (3) ◽  
pp. 46-52
Author(s):  
Anna A. Volf ◽  
Elena G. Fominykh ◽  
Mikhail P. Anisimov
Keyword(s):  
Nucleation Rate ◽  
Empirical Data ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Diffusion Chamber ◽  
Ambient Atmosphere ◽  
Gas Treatment ◽  
Carrier Gas ◽  
Nucleation Parameters ◽  
Set Up

Independent results for vapor nucleation rates illustrate the nucleation rates inconsistencies for identical vapor-gas systems at the same conditions. Nature of these inconsistencies is not yet understood enough. Assumption is discussed that a reason for the experimental data inconsistencies is appeared in the result of the carrier gas effects on nucleation. It was supposed for a long time that any carrier gas is an ambient atmosphere to keep the nucleation temperature only. The recent experimental results have shown that a vapor-gas nucleation needs to be treated in approximation of binary solutions, i. e. a composition axis is appeared in addition to axes of nucleation rate versus pressure. Each single line of a nucleation rate isotherm is transformed to surface in a three dimensional space of nucleation parameters. Flow diffusion chamber and expansion Wilson type set up data comparison are discussed on the example of the published empirical data. It was shown using a model system that these two experimental realizations produce the inconsistent trajectories in the space of nucleation parameters. That misfit induces the different origin data inconsistencies and demonstrates relevance of gas treatment as an individual component of a nucleating vapor-gas system.

A Geometrical treatment of the Correspondence between Lines in Threefold Space and Points of a Quadric in Fivefold space

1925 ◽  
Vol 22 (5) ◽  
pp. 694-699 ◽  
Author(s):  
H. W. Turnbull
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Quadratic Relation ◽  
Four Dimensions ◽  
Homogeneous Coordinates ◽  
Plücker Coordinates ◽  
Straight Line ◽  
Set Up ◽  
Image Position ◽  
Three Dimensional Space

§ 1. The six Plücker coordinates of a straight line in three dimensional space satisfy an identical quadratic relationwhich immediately shows that a one-one correspondence may be set up between lines in three dimensional space, λ, and points on a quadric manifold of four dimensions in five dimensional space, S5. For these six numbers pij may be considered to be six homogeneous coordinates of such a point.

scholarly journals Construction of the destination set of a dynamic system in $\mathbb{R}^3$

2021 ◽  
Vol 25 (2(36)) ◽  
pp. 83-94
Author(s):  
D. G. Kartashov ◽  
M. S. Tairova
Keyword(s):  
Dynamical Systems ◽  
Convex Hull ◽  
Dynamic System ◽  
Differential Inclusion ◽  
Support Function ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Arbitrary Point ◽  
Intersection Method ◽  
Three Dimensional Space

The article proposes two algorithms for the numerical construction of the convex hull of a set in three-dimensional space using its support function. The first uses the hyperplane intersection method to find the pivot points of a set. The second one is based on the deformation function and allows you to find an arbitrary point of the convex hull of a set, which is convenient in many applications. The algorithms are compared, and asymptotic complexities are found. The application of the proposed apparatus to finding the destination set of dynamical systems is shown. The dynamic system will be based on differential inclusion.

scholarly journals An overview of augmented visualization: observing the real world as desired

2018 ◽  
Vol 7 ◽  
Author(s):  
Shohei Mori ◽  
Hideo Saito
Keyword(s):  
Real World ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Open Problems ◽  
The Real ◽  
Real Objects ◽  
Point Image ◽  
Set Up ◽  
Background Image

Over 20 years have passed since a free-viewpoint video technology has been proposed with which a user's viewpoint can be freely set up in a reconstructed three-dimensional space of a target scene photographed by multi-view cameras. This technology allows us to capture and reproduce the real world as recorded. Once we capture the world in a digital form, we can modify it as augmented reality (i.e., placing virtual objects in the digitized real world). Unlike this concept, the augmented world allows us to see through real objects by synthesizing the backgrounds that cannot be observed in our raw perspective directly. The key idea is to generate the background image using multi-view cameras, observing the backgrounds at different positions and seamlessly overlaying the recovered image in our digitized perspective. In this paper, we review such desired view-generation techniques from the perspective of free-view point image generation and discuss challenges and open problems through a case study of our implementations.

scholarly journals Dynamic Sensor Matching for Parallel Point Cloud Data Acquisition

2021 ◽  
Author(s):  
Simone Müller ◽  
Dieter Kranzlmüller
Keyword(s):  
Point Cloud ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Object Perception ◽  
Point Clouds ◽  
Sensor Data ◽  
Virtual Object ◽  
Data Sets ◽  
Cloud Data ◽  
Digital Twins

Based on depth perception of individual stereo cameras, spatial structures can be derived as point clouds. The quality of such three-dimensional data is technically restricted by sensor limitations, latency of recording, and insufficient object reconstructions caused by surface illustration. Additionally external physical effects like lighting conditions, material properties, and reflections can lead to deviations between real and virtual object perception. Such physical influences can be seen in rendered point clouds as geometrical imaging errors on surfaces and edges. We propose the simultaneous use of multiple and dynamically arranged cameras. The increased information density leads to more details in surrounding detection and object illustration. During a pre-processing phase the collected data are merged and prepared. Subsequently, a logical analysis part examines and allocates the captured images to three-dimensional space. For this purpose, it is necessary to create a new metadata set consisting of image and localisation data. The post-processing reworks and matches the locally assigned images. As a result, the dynamic moving images become comparable so that a more accurate point cloud can be generated. For evaluation and better comparability we decided to use synthetically generated data sets. Our approach builds the foundation for dynamic and real-time based generation of digital twins with the aid of real sensor data.

scholarly journals Deep-Learning-Based Classification of Point Clouds for Bridge Inspection

2020 ◽  
Vol 12 (22) ◽  
pp. 3757
Author(s):  
Hyunsoo Kim ◽  
Changwan Kim
Keyword(s):  
Deep Learning ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Point Clouds ◽  
Dynamic Graph ◽  
Bridge Inspection ◽  
Cloud Data ◽  
Unit Value ◽  
Main Component

Conventional bridge maintenance requires significant time and effort because it involves manual inspection and two-dimensional drawings are used to record any damage. For this reason, a process that identifies the location of the damage in three-dimensional space and classifies the bridge components involved is required. In this study, three deep-learning models—PointNet, PointCNN, and Dynamic Graph Convolutional Neural Network (DGCNN)—were compared to classify the components of bridges. Point cloud data were acquired from three types of bridge (Rahmen, girder, and gravity bridges) to determine the optimal model for use across all three types. Three-fold cross-validation was employed, with overall accuracy and intersection over unions used as the performance measures. The mean interval over unit value of DGCNN is 86.85%, which is higher than 84.29% of Pointnet, 74.68% of PointCNN. The accurate classification of a bridge component based on its relationship with the surrounding components may assist in identifying whether the damage to a bridge affects a structurally important main component.

scholarly journals PHOTOGRAMMETRIC MODELING OF SUBTERRANEAN FEATURES THROUGH THREE-DIMENSIONAL SOFTWARE ANALYSIS

2020 ◽  
Vol XLIV-M-2-2020 ◽  
pp. 95-98
Author(s):  
J. Sepulveda ◽  
J. Capps ◽  
K. Johnson ◽  
C. Parada ◽  
A. Garcia ◽  
...  
Keyword(s):  
Point Cloud ◽  
Three Dimensional ◽  
Point Cloud Data ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Cloud Data ◽  
Software Analysis ◽  
Cave System ◽  
Set Up ◽  
The Impact

Abstract. LiDAR is a popular and accurate method for mapping that can be utilized for three-dimensional model analysis. However, the equipment set-up and usage can become tedious, and ultimately impractical when applied to locations that are remote and confined in nature. In this investigation, three-dimensional analysis was conducted within a cave system. With this, limitations of LiDAR technology in these conditions become prominent; mapping non-planar surfaces can cause a potential decrease of the quality of the point cloud data. In all, a LiDAR application would be an inefficient use of methodology to conduct this investigation. This prompted a need to set-up and conduct a photogrammetric based evaluation. With this, smartphone camera technology was used in conjunction with free-to-use software and three-dimensional modeling applications. Through the use of photogrammetric concepts and structure from motion software, a three-dimensional model of the cave can be generated. Long term, this model can also be utilized to document the impact and health of the cave system. For the methodology, the on-sight portion of the investigation relied heavily on smartphone camera technology. The procedure draws parallels to drone paths; specifically, two flight-plans were developed to evaluate different perspectives within a 15 by 15 meter space in the cave. Within each flight path, the use of photo overlapping techniques established a denser and more fluid point cloud model. Once the data was processed, two different three-dimensional models of the cave were created. From those models, the point cloud data was extracted in order to merge the two separate models. Afterwards, the models underwent several format conversions in order to import it into the Unity game engine. The final result is an accurate three-dimensional model of the cave that is viewable and playable in a simple video game platform.

scholarly journals On the 3D Track Planning for Electric Power Inspection Based on the Improved Ant Colony Optimization and A∗ Algorithm

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Zheng Huang ◽  
Xuefeng Zhai ◽  
Hongxing Wang ◽  
Hang Zhou ◽  
Hongwei Zhao ◽  
...  
Keyword(s):  
Ant Colony Optimization ◽  
Point Cloud ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Ant Colony ◽  
Point Cloud Data ◽  
Cloud Data ◽  
Shortest Route ◽  
Route Length ◽  
Three Dimensional Space

At present, multirotor drones are restricted by the control accuracy and cannot position accurately according to the accuracy of point cloud data. Also, track planning in three-dimensional space is much more complicated than that in two-dimensional space, which means that existing track planning methods cannot achieve fast planning. Meanwhile, most existing researches were implemented in quasi-three-dimensional space with the shortest route length as the objective function and omitted environmental impacts. To overcome these, this paper uses the grid method to segment point cloud data of the flying space via ArcGIS software according to the drone’s controlling accuracy. It also extracts the grid coordinate information and maps it to a three-dimensional matrix to build the model accurately. This paper sets the minimal energy consumption as the objective function and builds a track planning model based on the drone’s performance and natural wind constraints. The improved ant colony optimization and A∗ (ACO-A∗) algorithm are utilized to design this algorithm for a faster solution. That is, we use the improved ant colony optimization to quickly find a near-optimal track covering all viewpoints with the minimal energy consumption. The improved A∗ algorithm will be used for local planning for adjacent tracks passing through obstacles. In the designed simulation environment, the simulation results show that, to ensure that the same components are shot, the improved algorithm in this paper can save 62.88% energy compared to that of the Shooting Manual of Drone Inspection Images for Overhead Transmission Lines. Also, it can save 9.33% energy compared to a track with the shortest route length. Besides, the ACO-A∗ algorithm saves 96.6% time than the A∗ algorithm.

scholarly journals Digital evaluation of the leaf wall area of the grapevine (Vitis vinifera cv. Sauvignon) by using LIDAR measuring technology

2021 ◽  
Vol 44 (4) ◽  
pp. 74-81
Author(s):  
Peter Berk ◽  
Matej Sečnik ◽  
Andreja Urbanek Krajnc ◽  
Denis Stajnko
Keyword(s):  
Plant Protection ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Plant Protection Products ◽  
Base Station ◽  
Wall Area ◽  
Digital Reconstruction ◽  
Digital Evaluation ◽  
Set Up ◽  
The Right

A dosage rate reduction of plant protection products mixed with water, i.e. spray mixture, in a prescribed concentration in the vineyard will only be possible in the future, if the natural characteristics of vine canopy structures (leaf wall area) and canopy management are taken into account. In a practical experiment in the vineyard we evaluated the leaf wall area of the vine cv. Sauvignon on different segments on the left and right side of the vine canopy. We compared the results of manual measurements and laser measuring technology (LIDAR) with the corresponding algorithm, with which we enabled the digital reconstruction of the leaf wall area of the vine. The manual measurement of the leaf wall area was carried out using an automated image analyser. The digital system for measuring the leaf wall area on different segments consisted of a LIDAR sensor and a Differential Global Positioning System (hereinafter DGPS). To determine the exact DGPS position of the LIDAR sensor during the measurement, we set up a DGPS base station. Using the Excel software (CORREL function), we estimated the relationship between the dependent variable (digital number of points in the cloud) and an independent variable (leaf wall area, manually measured). An analysis of six randomly selected vines in the vineyard revealed the maximum value of the correlation coefficient r = 0.80 for the left side and r = 0.90 for the right side of the leaf wall area of the vine, respectively. In the near future the virtual three-dimensional space will provide more even control of spray mixture over the entire structure of the leaf wall area in the vineyard based on autonomous decision-making models.

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