Effect of Datum Securing Method on Precision of Mechanical Alignment System

1999 ◽  
Vol 122 (2) ◽  
pp. 350-359 ◽  
Author(s):  
Neville K. S. Lee ◽  
Keith K. C. Hon ◽  
Venus P. Y. Cheung ◽  
Ajay Joneja
Keyword(s):  
High Resolution ◽  
Monitoring System ◽  
Mechanical Alignment ◽  
Optical Position ◽  
Alignment System ◽  
Precision Level ◽  
Order Of Magnitude ◽  
Position Monitoring ◽  
Magnitude Improvement ◽  
The Way

In this research, the achievable precision level using mechanical datums for manufacturing has been studied. Specifically, the effect of how a datum is secured in a mechanical alignment system was studied with the aid of a high-resolution multidimensional optical position monitoring system developed for the purpose. The study shows that the way datum is secured can be a major factor affecting the alignment precision of a mechanical alignment system. For a datum prepared by randomly inserting dowel pins into precision bored holes, a common practice in industry, the precision level was found to be worse than 10 μm. The results also show that the precision level can be readily improved by addressing this major cause of inaccuracy. Different methods depending on manufacturing requirements and constraints have been proposed. Some of these simple procedures lead to more than an order of magnitude improvement in alignment precision. [S1087-1357(00)02001-3]

scholarly journals APEX, the Astrophysical Plasmadynamic EXplorer: An EUV High Resolution Spectroscopic Observatory

2005 ◽  
Vol 13 ◽  
pp. 796-798
Author(s):  
M Kowalski
Keyword(s):  
High Resolution ◽  
White Dwarfs ◽  
Effective Area ◽  
Order Of Magnitude ◽  
Magnitude Improvement

AbstractAPEX is a proposed Small Explorer satellite that will obtain high-resolution EUV spectra of white dwarfs, CVs, stellar coronae, and the local ISM. The APEX effective area (30-50 cm2) and resolution (~10,000) are an order of magnitude improvement over Chandra.

Effect of Mechanical Alignment System on Assembly Accuracy

2003 ◽  
Vol 125 (3) ◽  
pp. 595-608 ◽  
Author(s):  
Neville K. S. Lee ◽  
Grace H. Yu ◽  
J. Y. Chen ◽  
Ajay Joneja
Keyword(s):  
Simulation Models ◽  
Mechanical Alignment ◽  
Mechanical Assembly ◽  
Surface Errors ◽  
Error Surface ◽  
Assembly Accuracy ◽  
Alignment System ◽  
Order Of Magnitude ◽  
Proper Design ◽  
Selection Of

Mechanical means of positioning are frequently used in mechanical assembly processes. However, very little attention has been paid to the proper design and selection of mechanical alignment systems (MAS) for assembly processes. In this paper, we study the performance of different MAS in terms of assembly accuracy in the presence of the form error, surface waviness and surface roughness of the references surfaces. In particular, simulation models are used to investigate how the datum pin configuration, datum pin location and datum geometry of the MAS would affect the assembly accuracy in the presence of surface errors of the workpieces. Our investigation can provide insight into how to design MAS for optimum performance for assembly accuracy. Our analysis shows that over an order of magnitude of difference in assembly accuracy can exist between using properly designed MAS and poorly design MAS.

On-line alignment and astigmatism correction using a TV and personal computer

1993 ◽  
Vol 51 ◽  
pp. 202-203
Author(s):  
F. Hosokawa ◽  
Y. Kondo ◽  
T. Honda ◽  
Y. Ishida ◽  
M. Kersker
Keyword(s):  
High Resolution ◽  
Personal Computer ◽  
Block Diagram ◽  
Incident Beam ◽  
Ccd Camera ◽  
Alignment Procedure ◽  
Astigmatism Correction ◽  
Transmission Electron ◽  
Alignment System ◽  
On Line

High-resolution transmission electron microscopy must attain utmost accuracy in the alignment of incident beam direction and in astigmatism correction, and that, in the shortest possible time. As a method to eliminate this troublesome work, an automatic alignment system using the Slow-Scan CCD camera has been introduced recently. In this method, diffractograms of amorphous images are calculated and analyzed to detect misalignment and astigmatism automatically. In the present study, we also examined diffractogram analysis using a personal computer and digitized TV images, and found that TV images provided enough quality for the on-line alignment procedure of high-resolution work in TEM. Fig. 1 shows a block diagram of our system. The averaged image is digitized by a TV board and is transported to a computer memory, then a diffractogram is calculated using an FFT board, and the feedback parameters which are determined by diffractogram analysis are sent to the microscope(JEM- 2010) through the RS232C interface. The on-line correction system has the following three modes.

High-Density Memristor-CMOS Ternary Logic Family

2020 ◽  
Author(s):  
Xiaoyuan Wang ◽  
Pengfei Zhou ◽  
Jason Eshraghian ◽  
Chih-Yang Lin ◽  
Herbert Ho-Ching Iu ◽  
...  
Keyword(s):  
Indium Tin Oxide ◽  
Practical Implementation ◽  
Switching Speed ◽  
High Data ◽  
Fast Switching ◽  
Data Density ◽  
Order Of Magnitude ◽  
High Transconductance ◽  
Logic Functions ◽  
Magnitude Improvement

<div>This paper presents the first experimental demonstration</div><div>of a ternary memristor-CMOS logic family. We systematically</div><div>design, simulate and experimentally verify the primitive</div><div>logic functions: the ternary AND, OR and NOT gates. These are then used to build combinational ternary NAND, NOR, XOR and XNOR gates, as well as data handling ternary MAX and MIN gates. Our simulations are performed using a 50-nm process which are verified with in-house fabricated indium-tin-oxide memristors, optimized for fast switching, high transconductance, and low current leakage. We obtain close to an order of magnitude improvement in data density over conventional CMOS logic, and a reduction of switching speed by a factor of 13 over prior state-of-the-art ternary memristor results. We anticipate extensions of this work can realize practical implementation where high data density is of critical importance.</div>

scholarly journals A high-resolution solar spectrum 2000 Å–2200 Å

1970 ◽  
Vol 36 ◽  
pp. 271-273
Author(s):  
B. B. Jones ◽  
B. C. Boland ◽  
R. Wilson ◽  
S. T. F. Engstrom
Keyword(s):  
High Resolution ◽  
Solar Spectrum ◽  
Solar Image ◽  
Roll Control ◽  
North East ◽  
The North ◽  
Alignment System ◽  
Optical Alignment ◽  
South Axis ◽  
System Operating

A high-resolution solar spectrum in the range 2000–2200 Å was obtained in a recent flight of a sunpointing Skylark rocket. This was launched at 04.21 hr UT on April 22, 1969 from Woomera and reached an apogee of 178 km. An optical alignment system operating on the main vehicle pointing system gave a net stabilisation of ±3 arc sec in the position of the solar image relative to the spectrograph slit. The slit, of length 1.0 mm, was set in the north-east quadrant parallel to and 5 arc min from the north/south axis, its lower edge being 1 arc min from the equator. The roll control of ±2.5° was provided entirely by the standard Elliott Bros. type of vehicle stabilisation.

scholarly journals Incremental Construction of Generalized Voronoi Diagrams on Pointerless Quadtrees

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Quanjun Yin ◽  
Long Qin ◽  
Xiaocheng Liu ◽  
Yabing Zha
Keyword(s):  
Voronoi Diagrams ◽  
Surrounding Area ◽  
Repair Mechanism ◽  
Local Repair ◽  
Order Of Magnitude ◽  
Generalized Voronoi Diagrams ◽  
Incremental Construction ◽  
Coarse To Fine ◽  
Multiple Granularities ◽  
Magnitude Improvement

In robotics, Generalized Voronoi Diagrams (GVDs) are widely used by mobile robots to represent the spatial topologies of their surrounding area. In this paper we consider the problem of constructing GVDs on discrete environments. Several algorithms that solve this problem exist in the literature, notably the Brushfire algorithm and its improved versions which possess local repair mechanism. However, when the area to be processed is very large or is of high resolution, the size of the metric matrices used by these algorithms to compute GVDs can be prohibitive. To address this issue, we propose an improvement on the current algorithms, using pointerless quadtrees in place of metric matrices to compute and maintain GVDs. Beyond the construction and reconstruction of a GVD, our algorithm further provides a method to approximate roadmaps in multiple granularities from the quadtree based GVD. Simulation tests in representative scenarios demonstrate that, compared with the current algorithms, our algorithm generally makes an order of magnitude improvement regarding memory cost when the area is larger than210×210. We also demonstrate the usefulness of the approximated roadmaps for coarse-to-fine pathfinding tasks.

scholarly journals Real-Time Coil Position Monitoring System for Biomagnetic Measurements

2012 ◽  
Vol 36 ◽  
pp. 280-285 ◽  
Author(s):  
Daisuke Oyama ◽  
Yoshiaki Adachi ◽  
Masanori Higuchi ◽  
Jun Kawai ◽  
Koichiro Kobayashi ◽  
...  
Keyword(s):  
Real Time ◽  
Monitoring System ◽  
Position Monitoring

Beam position monitoring system upgrade for the TLS

2007 ◽  
Author(s):  
C. H. Kuo ◽  
P. C. Chiu ◽  
Jenny Chen ◽  
K.H. Hu ◽  
K. T. Hsu
Keyword(s):  
Monitoring System ◽  
Beam Position ◽  
Position Monitoring
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