scholarly journals Measurement Vertex Position of a Large Aspheric Mirror

2019 ◽  
Vol 9 (6) ◽  
pp. 1038 ◽  
Author(s):  
Jie Li ◽  
Fengtao Yan ◽  
Lin Chen ◽  
Jie Yang ◽  
Yongjian Wan
Keyword(s):  
Measurement Uncertainty ◽  
Measurement Accuracy ◽  
Mechanical Axis ◽  
Radius Of Curvature ◽  
Testing System ◽  
Laser Tracker ◽  
Position Measurement ◽  
Aspheric Mirror ◽  
Novel Method

We present a novel method to accurately measure the vertex position of a large aspheric mirror with a phasing measuring interferometer, a laser tracker, and a micro alignment telescope. The method consists of rotating the mirror by 180° about its mechanical axis and measuring the change in displacement. Use of a micro alignment telescope eliminates the need to adjust the mirror during the measurement, eases the alignment of the testing system, and improves the vertex position measurement accuracy. Using this method, we measured the vertex position of an aspheric mirror 1 m in diameter and 2 m in radius of curvature. The vertex position measurement uncertainty is 88 μm.

Method to Measure the Radius of Curvature of Conic Off-Axis Aspheric Mirror Using a Laser Tracker

2013 ◽  
Vol 50 (9) ◽  
pp. 091202
Author(s):  
郭玲玲 Guo Lingling ◽  
张星祥 Zhang Xingxiang ◽  
任建岳 Ren Jianyue ◽  
张立国 Zhang Liguo ◽  
付天骄 Fu Tianjiao
Keyword(s):  
Radius Of Curvature ◽  
Laser Tracker ◽  
Aspheric Mirror

Flowmetering in the Oil Industry

1986 ◽  
Vol 19 (5) ◽  
pp. 63-66 ◽  
Author(s):  
R C Gold
Keyword(s):  
Measurement Uncertainty ◽  
Crude Oil ◽  
Measurement Accuracy ◽  
Oil Production ◽  
Oil Industry ◽  
Different Types

The article traces the use of flowmeters in the production and processing of crude oil and its refined products. Emphasis is placed on meters used for accounting purposes and wherever possible, the significance of measurement uncertainty at the various stages of oil production is expressed in financial terms. The article concludes that improved measurement accuracy is more likely to be achieved from improved calibration and operating procedures than from the use of different types of flowmeters.

A Novel Method of Detecting Measurement Uncertainty of Voltage Deviation

2013 ◽  
Vol 805-806 ◽  
pp. 688-692
Author(s):  
Xin Fang ◽  
Xue Liang Huang ◽  
Yan Zhu
Keyword(s):  
Measurement Uncertainty ◽  
Power Quality ◽  
National Standards ◽  
Measurement Time ◽  
Time Interval ◽  
Basic Measurement ◽  
Voltage Deviation ◽  
Novel Method ◽  
Simulation Results

Nowadays, there are various devices to detect the power quality of AC grid, where uncertainty of voltage deviation is an important parameter to investigate the power quality. National standards specify several sinusoidal waveforms to detect it, usually implemented into the detecting devices. But these waveforms are not enough and a novel method of detecting measurement uncertainty of voltage deviation is proposed in this paper. A series of detection waveforms are designed using this method. The simulation results verify that the method is available to measure uncertainty of voltage deviation more accurately. Moreover, it can be used to justify whether the basic measurement time interval of voltage deviation meets IEC standard requirements.

Error sources and models of the laser tracker without a beam steering mirror

2021 ◽  
Author(s):  
Radoslav Choleva ◽  
Alojz Kopáčik
Keyword(s):  
Measurement Accuracy ◽  
Beam Steering ◽  
Systematic Errors ◽  
Error Modeling ◽  
Laser Tracker ◽  
High Demand ◽  
Error Sources ◽  
Error Models ◽  
Measurement Results

AbstractThe laser tracker is a widely used instrument in many industrial and metrological applications with high demand measurement accuracy. Imperfections in construction and misalignment of individual parts deliver systematic errors in the measurement results. All error sources need to be identified and reduced to the minimum to achieve the best possible accuracy. The paper summarizes error sources of the laser tracker without beam steering mirror with emphasis on error modeling. Descriptions of error models are provided for the static and kinematic type of measurement.

A novel method to improve the measurement accuracy of multilayer surface plasmon resonance sensor

Optik ◽  
2020 ◽  
Vol 222 ◽  
pp. 165016
Author(s):  
Jinglin Li ◽  
Zhangcong Xia ◽  
Fenghong Chu ◽  
Lu Zhang ◽  
Lei Liu ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Measurement Accuracy ◽  
Surface Plasmon Resonance Sensor ◽  
Resonance Sensor ◽  
Novel Method

Miniaturization of an interferometric distance sensor employing diffractive optics

2014 ◽  
Vol 3 (4) ◽  
Author(s):  
Nektarios Koukourakis ◽  
Robert Kuschmierz ◽  
Michael Bohling ◽  
Jürgen Jahns ◽  
Andreas Fischer ◽  
...  
Keyword(s):  
Measurement Uncertainty ◽  
Measurement Techniques ◽  
Turbine Blades ◽  
Numerical Aperture ◽  
Optical Element ◽  
Systematic Measurement ◽  
Position Measurement ◽  
Common Path ◽  
The Common ◽  
Path Detection

AbstractIn order to improve safety, lifetime and energy efficiency of turbo machines, the behavior of the turbine blades has to be monitored during operation. This is a great challenge for metrology, since small, robust and non-contact position measurement techniques are required that offer both micrometer accuracy and microsecond temporal resolution. The Laser-Doppler-Distance (LDD) -Sensor proved to be an adequate technique to perform such measurements. However, the usage in turbo machines requires a miniaturized and temperature-stable sensor-head. In this paper we introduce a miniaturized design of the LDD-sensor that is based on common-path detection. First results indicated that the numerical aperture of the common-path detection is small in comparison to former implementations that used separate paths for illumination and detection. We find that decreasing the numerical aperture strongly increases the systematic measurement uncertainty. For this purpose a novel diffractive optical element containing a diffracting-lens was designed and used to increase the numerical aperture of the common-path detection without affecting the sensor size. Experiments prove that the new element reduces the relative systematic measurement uncertainty by a factor of ten. The mean systematic position measurement uncertainty amounts to Δ

Self-Sensing in Fault Tolerant Magnetic Bearings

1999 ◽  
Author(s):  
Dominick Montie ◽  
Eric Maslen
Keyword(s):  
Measurement Accuracy ◽  
Fault Tolerant ◽  
Failure Mechanisms ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Position Measurement ◽  
Sensors And Actuators ◽  
Convergence Control ◽  
Fault Tolerant Systems ◽  
Fault State

Several schemes have recently been proposed for achieving either fault tolerance or self-sensing in magnetic bearings. The present work describes the fundamental connection between ability to actuate and ability to sense in a partially failed magnetic bearing system. This relationship is then exploited to construct a self-sensing scheme which operates in the presence of detectable actuator or amplifier faults. Such an approach is advantageous in fault tolerant systems because it reduces or eliminates the need to address potential independent failure mechanisms in sensors and actuators. Based on a model reference parameter estimation mechanism, the self-sensing scheme is shown to provide acceptable position measurement accuracy and bandwidth under various actuator/amplifier faults which are actuator tolerable. Estimates of increase in noise floor and loss of bandwidth under fault conditions are provided. The issue of estimator convergence under fault conditions is examined in detail with comments on implementation complexity arising from scheduling convergence control on fault state.

Computing Surface Parameter of Conic Aspheric Mirror with Singular Value Decomposition

2013 ◽  
Vol 631-632 ◽  
pp. 1363-1366
Author(s):  
Yong Luo
Keyword(s):  
Singular Value Decomposition ◽  
Singular Value ◽  
Radius Of Curvature ◽  
Surface Parameter ◽  
Aspheric Mirror ◽  
Value Decomposition ◽  
Svd Method

The result of null testing is usually used as the criterion in the fabricating process of aspheric mirrors. To ensure the accuracy of paraxial radius of curvature and conic constant is important when the null compensator emerges a problem. From the equation of conic aspheric mirror, we derive a set of algorithm from which the paraxial radius of curvature R and conic constant k can be obtained by using Singular Value Decomposition (SVD) method. The simulating result of an aspheric mirror with an aperture of 1229mm is presented and the solving precision reaches △R=0.1% and △k=0.14%. Thus the supplement to null testing of aspheric mirror is achieved effectively.

Measurement uncertainty analysis on laser tracker combined with articulated CMM

2013 ◽  
Author(s):  
Hui-ning Zhao ◽  
Lian-dong Yu ◽  
Yun Du ◽  
Hai-yan Zhang
Keyword(s):  
Uncertainty Analysis ◽  
Measurement Uncertainty ◽  
Laser Tracker
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