An Optimized Magnet-Coil Force Actuator and Its Application to Precision Elastic Mechanisms

1990 ◽  
Vol 204 (4) ◽  
pp. 243-253 ◽  
Author(s):  
S T Smith ◽  
D G Chetwynd
Keyword(s):  
Short Range ◽  
Open Loop ◽  
Coil Design ◽  
Solenoid Coil ◽  
Positional Accuracy ◽  
Design Models ◽  
Design Considerations ◽  
Linear Spring ◽  
Magnet Coil ◽  
Better Than

Sprung translation mechanisms driven by electromagnetic force actuators are often used to produce controllable motions. This paper is concerned with one family of such devices incorporating linear spring mechanisms suitable for short-range, high-precision applications. In these, a permanent magnet is attached to the movable translating stage which is, in turn, surrounded by a solenoid coil attached to a fixed datum. Design considerations are discussed, principally an optimum dimensional design for a uniformly wound circular cylindrical coil. Design models are verified by the construction of a simple device in steel and aluminium which demonstrates an open-loop positional accuracy of better than 0.5 per cent over a displacement range of 100 nm to 50 μm.

scholarly journals CPC2 Reduction with Hipparcos and Proper Motions in The Southern Hemisphere

1998 ◽  
Vol 11 (1) ◽  
pp. 551-551
Author(s):  
N. Zacharias ◽  
M.I. Zacharias ◽  
C. de Vegt ◽  
C.A. Murray
Keyword(s):  
Southern Hemisphere ◽  
Systematic Errors ◽  
Reference Star ◽  
Proper Motions ◽  
Positional Accuracy ◽  
Star Catalog ◽  
Naval Observatory ◽  
Celestial Reference System ◽  
First Time ◽  
Better Than

The Second Cape Photographic Catalog (CPC2) contains 276,131 stars covering the entire Southern Hemisphere in a 4-fold overlap pattern. Its mean epoch is 1968, which makes it a key catalog for proper motions. A new reduction of the 5687 plates using on average 40 Hipparcos stars per plate has resulted in a vastly improved catalog with a positional accuracy of about 40 mas (median value) per coordinate, which comes very close to the measuring precision. In particular, for the first time systematic errors depending on magnitude and color can be solved unambiguously and have been removed from the catalog. In combination with the Tycho Catalogue (mean epoch 1991.25) and the upcoming U.S. Naval Observatory CCD Astrograph Catalog (UCAC) project proper motions better than 2 mas/yr can be obtained. This will lead to a vastly improved reference star catalog in the Southern Hemisphere for the final Astrographic Catalogue (AC) reductions, which will then provide propermotions for millions of stars when combined with new epoch data. These data then will allow an uncompromised reduction of the southern Schmidt surveys on the International Celestial Reference System (ICRS).

scholarly journals Coil design considerations for deep transcranial magnetic stimulation

2014 ◽  
Vol 125 (6) ◽  
pp. 1202-1212 ◽  
Author(s):  
Zhi-De Deng ◽  
Sarah H. Lisanby ◽  
Angel V. Peterchev
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Coil Design ◽  
Design Considerations

Twin Coil Design Considerations for Depth and Focality in Transcranial Magnetic Stimulation

2018 ◽  
Vol 54 (11) ◽  
pp. 1-5
Author(s):  
Siyuan Chang ◽  
Xile Wei ◽  
Zhen Zhang ◽  
Jiang Wang ◽  
Meili Lu ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Magnetic Stimulation ◽  
Coil Design ◽  
Design Considerations

Coil design considerations for a high-frequency electromagnetic induction sensing instrument

2016 ◽  
Author(s):  
John B. Sigman ◽  
Benjamin E. Barrowes ◽  
Yinlin Wang ◽  
Hollis J. Bennett ◽  
Janet E. Simms ◽  
...  
Keyword(s):  
High Frequency ◽  
Electromagnetic Induction ◽  
Coil Design ◽  
Design Considerations

Consideration of Optimal Magnet Coil Design for 1300 MWth Coal Combustion Magnetohydrodynamic Generator

1993 ◽  
Vol 32 (Part 1, No. 7) ◽  
pp. 3270-3275
Author(s):  
Ryo Nishimura ◽  
Yoshiaki Aoki ◽  
Naoyuki Kayukawa
Keyword(s):  
Coal Combustion ◽  
Coil Design ◽  
Magnet Coil

Single-camera visual odometry to track a surgical X-ray C-arm base

2017 ◽  
Vol 231 (12) ◽  
pp. 1140-1151 ◽  
Author(s):  
Hooman Esfandiari ◽  
Derek Lichti ◽  
Carolyn Anglin
Keyword(s):  
Tracking System ◽  
Dead Reckoning ◽  
Visual Odometry ◽  
Single Camera ◽  
Positional Accuracy ◽  
System A ◽  
Homography Estimation ◽  
Joint Tracking ◽  
Application Specific ◽  
Better Than

This study provides a framework for a single-camera odometry system for localizing a surgical C-arm base. An application-specific monocular visual odometry system (a downward-looking consumer-grade camera rigidly attached to the C-arm base) is proposed in this research. The cumulative dead-reckoning estimation of the base is extracted based on frame-to-frame homography estimation. Optical-flow results are utilized to feed the odometry. Online positional and orientation parameters are then reported. Positional accuracy of better than 2% (of the total traveled distance) for most of the cases and 4% for all the cases studied and angular accuracy of better than 2% (of absolute cumulative changes in orientation) were achieved with this method. This study provides a robust and accurate tracking framework that not only can be integrated with the current C-arm joint-tracking system (i.e. TC-arm) but also is capable of being employed for similar applications in other fields (e.g. robotics).

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