Visibility Analysis for Assembly Fixture Calibration Using Screen Space Transformation

2004 ◽  
Vol 127 (3) ◽  
pp. 622-634 ◽  
Author(s):  
Zhenyu Kong ◽  
Wenzhen Huang ◽  
Dariusz Ceglarek
Keyword(s):  
Dimensional Space ◽  
Manufacturing Processes ◽  
Navigation Systems ◽  
Visibility Analysis ◽  
Space Transformation ◽  
Quality Of Products ◽  
Multistation Assembly ◽  
Screen Space ◽  
Calibration Time ◽  
Assembly Fixture

In a number of manufacturing processes—tooling installation, calibration, and maintenance—guarantee the precision of fixtures and play important roles toward the overall quality of products. Recently, a new type of measurement equipment called a “laser tracker” was developed and utilized for assembly fixture calibration to shorten calibration time and improve the accuracy of the currently used theodolite systems. Though calibration of the assembly fixture is critical for product quality, as such, calibration time creates a significant burden for productivity of multistation assembly processes. In order to shorten calibration lead time, the number of necessary setups, determined by visibility analysis, needs to be minimized. This paper presents a screen space transformation-based visibility analysis that allows minimizing the number of setups. The screen space transformation is applied to transform the visibility problem from three- to two-dimensional space, thus, efficiently solving the visibility problem. A case study illustrates the procedure and verifies the validity of the proposed methodology. This methodology can be applied not only for manufacturing processes, such as in-line fixture calibration, but also toward analysis and optimization of AGVs, robot navigation systems, and building security.

Visibility Analysis for Assembly Fixture Calibration Using Screen Space Transformation

2003 ◽  
Author(s):  
Zhenyu Kong ◽  
Wenzhen Huang ◽  
Dariusz Ceglarek
Keyword(s):  
Visibility Analysis ◽  
Space Transformation ◽  
Significant Burden ◽  
New Type ◽  
Quality Of Products ◽  
Screen Space ◽  
Calibration Time ◽  
Assembly Fixture

In a number of manufacturing processes, tooling installation, calibration and maintenance guarantee the precision of fixtures and play important roles towards the overall quality of products. Recently a new type of measurement equipment called “laser tracker” was developed and utilized for assembly fixture calibration to shorten calibration time and improve the accuracy of the currently used theodolite systems. Though, the calibration of assembly fixture is critical for product quality, the calibration time creates significant burden for productivity of multi-station assembly processes. In order to shorten the calibration lead time, the number of necessary calibration setups which is determined by visibility analysis needs to be minimized. This paper presents a screen space transformation based visibility analysis that allows minimizing the number of setups. The screen space transformation is applied to transform the visibility problem from 3D to 2D space, consequently the visibility problem can be solved efficiently. A case study illustrates the procedure and verifies the validity of the proposed methodology.

The Design of Experiments as a Methodological Framework for the Improvement of Manufacturing Processes

2020 ◽  
pp. 270-298
Author(s):  
Sukey Nakasima-López ◽  
Mydory Oyuky Nakasima-López ◽  
Karla Frida Madrigal Estrada ◽  
Erika Beltrán Salomón
Keyword(s):  
Design Of Experiments ◽  
New Products ◽  
Manufacturing Processes ◽  
Methodological Framework ◽  
Maintenance And Repair ◽  
Cycle Times ◽  
Innovative Products ◽  
Quality Of Products ◽  
Different Levels

Industries seek changes in manufacturing processes by designing or redesigning them, to improve the quality of products, reduce costs and cycle times, change materials, modify methods, design innovative products, among others. Facing these demands requires a powerful methodological framework known as Design of Experiments. Most of literature focuses on the application of these techniques in the areas of statistics and quality. However, the variety of problems facing engineers in industry is wide and includes different levels of complexity, ranging from the design of new products, improvement of design, maintenance, control and improvement of manufacturing processes, maintenance and repair of products, among others. This chapter provides the reader different applications of this methodology in industry, to highlight the importance and benefits of knowing and applying these techniques. It will present the application of this methodology in a general way and finally, it will discuss different case studies that use this methodology in industry.

scholarly journals Performance Evaluation Using Multivariate Non-Normal Process Capability

Processes ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 833 ◽  
Author(s):  
Alatefi ◽  
Ahmad ◽  
Alkahtani
Keyword(s):  
Manufacturing Industry ◽  
Process Capability ◽  
Quality Characteristic ◽  
Process Capability Indices ◽  
Manufacturing Processes ◽  
Capability Indices ◽  
Skewness Reduction ◽  
Quality Of Products

Process capability indices (PCIs) have always been used to improve the quality of products and services. Traditional PCIs are based on the assumption that the data obtained from the quality characteristic (QC) under consideration are normally distributed. However, most data on manufacturing processes violate this assumption. Furthermore, the products and services of the manufacturing industry usually have more than one QC; these QCs are functionally correlated and, thus, should be evaluated together to evaluate the overall quality of a product. This study investigates and extends the existing multivariate non-normal PCIs. First, a multivariate non-normal PCI model from the literature is modeled and validated. An algorithm to generate non-normal multivariate data with the desired correlations is also modeled. Then, this model is extended using two different approaches that depend on the well-known Box–Cox and Johnson transformations. The skewness reduction is further improved by applying heuristics algorithms. These two approaches outperform the investigated model from the literature because they can provide more precise results regardless of the skewness type. The comparison is made based on the generated data and a case study from the literature.

scholarly journals Increasing the Usability of Pedestrian Navigation Interfaces by means of Landmark Visibility Analysis

2013 ◽  
Vol 66 (4) ◽  
pp. 523-537 ◽  
Author(s):  
Ioannis Delikostidis ◽  
Juri Engel ◽  
Bas Retsios ◽  
Corné P.J.M. van Elzakker ◽  
Menno-Jan Kraak ◽  
...  
Keyword(s):  
Specific Information ◽  
3D Analysis ◽  
Navigation Systems ◽  
Visibility Analysis ◽  
Pedestrian Navigation ◽  
3D City Model ◽  
Efficiency And Effectiveness ◽  
Algorithmic Framework ◽  
City Model ◽  
User Friendly

Communicating location-specific information to pedestrians is a challenging task which can be aided by user-friendly digital technologies. In this paper, landmark visibility analysis, as a means for developing more usable pedestrian navigation systems, is discussed. Using an algorithmic framework for image-based 3D analysis, this method integrates a 3D city model with identified landmarks and produces raster visibility layers for each one. This output enables an Android phone prototype application to indicate the visibility of landmarks from the user's actual position. Tested in the field, the method achieves sufficient accuracy for the context of use and improves navigation efficiency and effectiveness.

EncCon: An Approach to Constructing Interactive Visualization of Large Hierarchical Data

2005 ◽  
Vol 4 (1) ◽  
pp. 1-21 ◽  
Author(s):  
Quang Vinh Nguyen ◽  
Mao Lin Huang
Keyword(s):  
Hierarchical Structure ◽  
Experimental Evaluation ◽  
Dimensional Space ◽  
Two Dimensional ◽  
Hierarchical Data ◽  
Division Algorithm ◽  
Layout Algorithm ◽  
The Hierarchical Structure ◽  
A New Technique ◽  
Screen Space

This paper describes a new technique called EncCon for visualizing and navigating large hierarchical information. This technique consists of two components: visualization and navigation. Visualization uses a fast enclosure + connection method to calculate the geometrical layout for the display of large hierarchies in a two-dimensional space. Our technique uses a rectangular division algorithm for recursively positioning the graph. This visualization aims to maximize the utilization of display space while retaining a good geometrical layout as well as a clear (explicit) presentation of the hierarchical structure of graphs. This paper also presents an experimental evaluation of EncCon's layout algorithm. Besides the layout algorithm, EncCon uses a new focus + context viewing technique for the navigation of large hierarchies. We use the zooming + layering concept to achieve the focus + context viewing, rather than the traditional enlarge + embedded concept, which is used by most of the available focus + context techniques. Technically, it employs semi-transparency to achieve the display of two layers of information in z-coordination at the same visualization. Both context view and detail view are drawn at two separate layers. These layers are then displayed in an overlapped manner at the same physical screen space.

Simplified Manufacturing Through a Metamorphic Process for Compliant Ortho-Planar Mechanisms

2005 ◽  
Author(s):  
Daniel W. Carroll ◽  
Spencer P. Magleby ◽  
Larry L. Howell ◽  
Robert H. Todd ◽  
Craig P. Lusk
Keyword(s):  
Design Process ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Manufacturing Processes ◽  
Two Dimensional ◽  
Planar Mechanisms ◽  
Three Dimensional Space ◽  
Metamorphic Mechanisms

Most simplified manufacturing processes generally result in two-dimensional features. However, most products are three-dimensional. Devices that could be manufactured through simplified manufacturing processes, but function in a three-dimensional space, would be highly desirable — especially if they require little assembly. Compliant ortho-planar metamorphic mechanisms (COPMMS) can be fabricated through simplified manufacturing processes, and then metamorphically transformed into a new configuration where they are no longer bound by the limitations of ortho-planar behavior. The main contributions of this paper are the suggestion of COPMM definitions, an investigation into the morphing process, and the description of a COPMM design process. This work also contributes a case study in designing COPMMs to meet particular design objectives.

Visibility Analysis and Synthesis for Assembly Fixture Certification Using Theodolite Systems

1999 ◽  
Vol 123 (1) ◽  
pp. 83-89 ◽  
Author(s):  
Hung-Kuei Chen ◽  
S. Jack Hu ◽  
T. C. Woo
Keyword(s):  
Process Design ◽  
Measuring Systems ◽  
Visibility Analysis ◽  
Potential Measurement ◽  
Improve Measurement ◽  
Certification Procedure ◽  
Analysis And Synthesis ◽  
Automotive Sheet ◽  
Assembly Fixture ◽  
Sheet Metal Assembly

In automotive sheet metal assembly, part positioning and clamping is accomplished by fixtures consisting of fixture elements, such as pins and blocks. The locations of these elements are determined during process design and need to be certified during the construction and installation of an assembly line. Usually, theodolite systems are used to certify the locations of these elements by measuring the trihedron points on the fixture elements. However, no systematic method exists for the selection and placement of measuring systems. As a result, the current certification procedure is very time-consuming and is prone to error. This paper presents an algorithm for the optimal setup and placement of theodolite systems based on visibility analysis and synthesis. For a given tooling fixture, the visibility map is introduced to represent the set of potential measurement locations when a number of fixture elements are to be measured. From the set of potential measurement locations, an optimal setup will be selected based on minimizing the number of theodolite heads by optimally locating these theodolites. This approach will minimize measurement setups and improve measurement accuracy.

Research of Intelligent Localization of Target for Manipulator Based on the Monocular Vision

2012 ◽  
Vol 246-247 ◽  
pp. 22-27
Author(s):  
Zheng Zhang ◽  
Xiao Wei Liu ◽  
Guang You Yang
Keyword(s):  
Coordinate System ◽  
Robot Manipulator ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Image Plane ◽  
Calculation Model ◽  
Monocular Vision ◽  
3D Space ◽  
Space Transformation ◽  
World Coordinate System

A kind of calculation model of 3D space transformation is introduced, which is applicable to the monocular vision of robot manipulator, and the three-dimensional space plane mapping problem of image plane to the actual horizontal plane of monocular vision has been solved. It transforms the imaging coordinate system of target in monocular vision into the world coordinate system of the manipulator, so as to calculate the relative position of targets and the manipulator. The algorithm has better accuracy and reliability, which is proved by contrasting and testing the calculation result of object coordinate system transformed to the actual position coordinates to the sampling points in embedded platform.

scholarly journals A New Perspective on Low-Cost MEMS-Based AHRS Determination

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1383
Author(s):  
Neda Navidi ◽  
Rene Landry
Keyword(s):  
Reference System ◽  
Dimensional Space ◽  
Low Cost ◽  
Three Dimensional ◽  
Navigation Systems ◽  
Adaptive Kalman Filter ◽  
Initial Attitude ◽  
New Perspective ◽  
And Control ◽  
Three Dimensional Space

Attitude and heading reference system (AHRS) is the term used to describe a rigid body’s angular orientation in three-dimensional space. This paper describes an AHRS determination and control system developed for navigation systems by integrating gyroscopes, accelerometers, and magnetometers signals from low-cost MEMS-based sensors in a complementary adaptive Kalman filter. AHRS estimation based on the iterative Kalman filtering process is required to be initialized first. A new method for AHRS initialization is proposed to improve the accuracy of the initial attitude estimates. Attitude estimates derived from the initialization and iterative adaptive filtering processes are compared with the orientation obtained from a high-end reference system. The improvement in the accuracy of the initial orientation as significant as 45% is obtained from the proposed method as compared with other selected techniques. Additionally, the computational process is reduced by 96%.

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