Reviving the inter-laboratory comparison measurement results

2019 ◽  
Vol 42 (4) ◽  
pp. 823-831
Author(s):  
Mahammed Arif Sanjid ◽  
Sanjoy K Ghoshal ◽  
Mrinal Sen
Keyword(s):  
Interlaboratory Comparison ◽  
Systematic Errors ◽  
Measuring System ◽  
Internal Diameter ◽  
Key Comparison ◽  
Comparison Results ◽  
Measurement Results ◽  
Comparison Measurements ◽  
Achievable Accuracy ◽  
Comparison Data

Key comparison measurements serve as an ultimate tool of quality assurance of results. Whenever the inter-comparison results indicate inconsistency, the participating laboratory needs to take the corrective actions. Practically, the systematic errors involved in the measuring system confines the achievable accuracy. Therefore, the corrective action involves either empirically determine the influences afresh or intuitively reassigns these error values. Alternatively, an analytical method based on inter laboratory comparison results is proposed. The novelty of the proposal is considering task-specific errors in the model that is used for the analysis of interlaboratory comparison results. Without accounting the uncertainties of task-specific errors, the analysis grows complicated and even sometimes it is not feasible. To supplement the proposed method, task-specific errors due to the imperfect geometry of ring gauge, practical inability in implementing the measurement, and unattended environmental influences are explored. The proposed method is demonstrated using some internal diameter key comparison data. The systematic errors responsible for the outlier in the measurement comparison are clearly distinguished.

Research on Precision Measuring System for Motor Speed

2012 ◽  
Vol 588-589 ◽  
pp. 1103-1107
Author(s):  
Yu Hai Gu ◽  
Qiu Shi Han ◽  
Xiao Li Xu ◽  
Hai Tao Zhang
Keyword(s):  
Control Systems ◽  
Precise Measurement ◽  
Serial Communication ◽  
Measuring System ◽  
Motor Speed ◽  
Precision Measuring ◽  
Measurement Results ◽  
Improve Accuracy ◽  
Improving Accuracy ◽  
Motor Control Systems

In order to improve accuracy of measuring motor speed in precision motor control systems, a method of precise measurement of speed with CPLD is proposed, which measures the truncated parts of the measured pulse on the basis of measuring raster count pulse within the equal period, and takes them as compensation, thus improving accuracy of measuring the raster pulse. In this paper, a speed measuring formula is given. Measuring system is provided with parallel and serial communication interfaces for output of measurement results.

Estimation of uncertainty in olfactometry

2009 ◽  
Vol 59 (7) ◽  
pp. 1409-1413 ◽  
Author(s):  
T. Higuchi
Keyword(s):  
Measurement Uncertainty ◽  
Interlaboratory Comparison ◽  
Collaborative Study ◽  
Estimation Procedure ◽  
Measurement Model ◽  
Standard Uncertainty ◽  
Expanded Uncertainty ◽  
Collaborative Test ◽  
Measurement Results ◽  
Estimation Of Uncertainty

Estimation of uncertainty in odour measurement is essential to the interpretation of the measurement results. The fundamental procedure for the estimation of measurement uncertainty comprises the specification of the measurement process, expression of the measurement model and all influences, evaluation of the standard uncertainty of each component, calculation of the combined standard uncertainty, determination of a coverage factor, calculation of the expanded uncertainty and reporting. Collaborative study such as interlaboratory comparison of olfactometry yields performance indicators of the measurement method including repeatability and reproducibility. Therefore, the use of collaborative test results for measurement uncertainty estimation according to ISO/TS 21748 and ISO 20988 is effective and reasonable. Measurement uncertainty of the triangular odour bag method was estimated using interlaboratory comparison data from 2003 to 2007 on the basis of the simplest model of statistical analysis, and the expanded uncertainty of odour index ranged between 3.1 and 6.7. On the basis of the establishment of the estimation procedure for uncertainty, a coherent interpretation method for the measurement results will be proposed and more effective and practical quality control of olfactometry will be available.

The evaluation of key comparison data

Metrologia ◽  
2002 ◽  
Vol 39 (6) ◽  
pp. 589-595 ◽  
Author(s):  
M G Cox
Keyword(s):  
Key Comparison ◽  
Comparison Data

scholarly journals The Concept of Geodetic Analyses of the Measurement Results Obtained by Hydrostatic Leveling

Geosciences ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 406
Author(s):  
Kamiński ◽  
Makowska
Keyword(s):  
Structural Health Monitoring ◽  
Kalman Filtering ◽  
Health Monitoring ◽  
Systematic Errors ◽  
Monitoring Systems ◽  
Measurement Results ◽  
Vertical Displacements ◽  
Complete Computation ◽  
Computation Scheme ◽  
Health Monitoring Systems

The article discusses the issue of hydrostatic leveling. Its application is presented in structural health monitoring systems in order to determine vertical displacements of controlled points. Moreover, the article includes a complete computation scheme that utilizes the estimation from observation differences, allowing the elimination of the influence of individual sensors’ systematic errors. The authors suggest two concepts of processing the measurement results depending on the sensors’ connection method. Additionally, the second concept is extended by the elements allowing the prediction of the displacements by means of Kalman filtering.

scholarly journals Evaluation of Terrestrial Laser Scanner Accuracy in the Control of Hydrotechnical Structures

2017 ◽  
Vol 39 (4) ◽  
pp. 45-57 ◽  
Author(s):  
Zbigniew Muszyński ◽  
Jarosław Rybak
Keyword(s):  
Laser Scanning ◽  
Reference Beam ◽  
Terrestrial Laser Scanning ◽  
Systematic Errors ◽  
Ground Movement ◽  
Engineering Practice ◽  
Reference Structure ◽  
Advantages And Disadvantages ◽  
Measurement Results ◽  
Horizontal Displacements

Abstract In many cases of monitoring or load testing of hydrotechnical structures, the measurement results obtained from dial gauges may be affected by random or systematic errors resulting from the instability of the reference beam. For example, the measurement of wall displacement or pile settlement may be increased (or decreased) by displacements of the reference beam due to ground movement. The application of surveying methods such as high-precision levelling, motorized tacheometry or even terrestrial laser scanning makes it possible to provide an independent reference measurement free from systematic errors. It is very important in the case of walls and piles embedded in the rivers, where the construction of reference structure is even more difficult than usually. Construction of an independent reference system is also complicated when horizontal testing of sheet piles or diaphragm walls are considered. In this case, any underestimation of the horizontal displacement of an anchored or strutted construction leads to an understated value of the strut’s load. These measurements are even more important during modernization works and repairs of the hydrotechnical structures. The purpose of this paper is to discuss the possibilities of using modern measurement methods for monitoring of horizontal displacements of an excavation wall. The methods under scrutiny (motorized tacheometry and terrestrial laser scanning) have been compared to classical techniques and described in the context of their practical use on the example hydrotechnical structure. This structure was a temporary cofferdam made from sheet pile wall. The research continuously conducted at Wroclaw University of Science and Technology made it possible to collect and summarize measurement results and practical experience. This paper identifies advantages and disadvantages of both analysed methods and presents a comparison of obtained measurement results of horizontal displacements. In conclusion, some recommendations have been formulated, which are relevant from the point of view of engineering practice.

scholarly journals The measurements results adjustment by the Least Square Method

2021 ◽  
Vol 1 ◽  
pp. 1-8
Author(s):  
Oleksandr Samoilenko ◽  
Yurii Kuzmenko
Keyword(s):  
Reference Value ◽  
Least Square Method ◽  
Systematic Errors ◽  
Least Square ◽  
Key Comparisons ◽  
System Of Equations ◽  
The Third ◽  
Measurement Results ◽  
Free Case ◽  
Degrees Of Equivalence

The method for processing of the measurement results obtained from Comite International des Poids et Measures (CIPM) Key, Regional Metrology Organizations (RMO) or supplementary comparisons, from the proficiency testing by interlaboratory comparisons and the calibrations is proposed. It is named by authors as adjustment by least square method (LSM). Additive and multiplicative parameters for each measuring standard of every particular laboratory will be the results of this adjustment. As well as the parameters for each artifact. The parameters of the measurements standards are their additive and multiplicative degrees of equivalence from the comparison and the estimations of the systematic errors (biases) from calibrations. The parameters of the artifacts are the key comparisons reference value from the comparison and the assigned quantity values from the calibrations. The adjustment is considered as a way to solving a problem of processing the great amount of homogeneous measurements with many measuring standards at a different comparison levels (CIPM, RMO or supplementary), including connected problems. Four different cases of the adjustments are considered. The first one is a free case of adjustment. It was named so because of the fact that none of participants has any advantage except their uncertainties of measurements. The second one is a fixed case of adjustment. Measuring results of RMO and supplementary comparisons are rigidly linked to additive and multiplicative parameters of measuring standards of particular laboratories participated in CIPM key comparisons. The third one is a case of adjustment with dependent equations. This one is not so rigidly linked of the new comparisons results to previous or to some other comparisons as for fixed case. It means that the new results of comparisons are influenced by the known additive and multiplicative parameters and vice versa. The fourth one is a free case of adjustment with additional summary equations. In that case certain checking equations are added to the system of equations. So, the sum of parameters multiplied by their weights of all measurement standards for particular laboratories participated in comparisons should be equal to zero.

scholarly journals Features of interlaboratory comparison methods when measuring vibroacoustic parameters

2021 ◽  
Author(s):  
AV Sterlikov ◽  
YuV Kurilenko ◽  
AA Voronkov
Keyword(s):  
Pid Controller ◽  
Interlaboratory Comparison ◽  
Physical Simulation ◽  
Acoustic Noise ◽  
Automated System ◽  
Proportional Integral Derivative ◽  
Noise Sources ◽  
Vibration Stability ◽  
Measurement Results ◽  
Airborne Ultrasound

External quality control in the form of interlaboratory comparisons (ILCs) is an important criterion of the testing laboratory competence. The study was aimed to summarize the approaches to developing objects for proficiency testing (OPT) based on physical simulation of acoustic noise sources, airborne ultrasound, vibration, and the practice of their use for ILC. Analysis of the OPT effectiveness based on physical simulation of factors, the test benches (TBs), was performed based on their testing and certification results, as well as on the results of appropriate ILCs. The results of using TB as OPT are considered for the following factors: acoustic noise, airborne ultrasound, and vibration. When measuring acoustic noise, TB played back the acoustic noise record with high stability. ILC involving measurement of airborne ultrasound was performed the same way, however, the frequency of the acoustic signal being reproduced was in the range of 11–22 kHz. TBs, based on a manual mechanized tool and a platform equipped with electromechanical agitator, were developed for ILC involving the measurement of local and general vibration. Stability of vibration generated was provided by means of the automated system for maintaining the set level with feedback and proportional integral derivative (PID) controller. When arranging and performing ILCs involving measurement of noise and vibration, a crucial role is played by the methods developed specifically for ILCs, allowing one to take into account all the conditions that affect the measurement results.

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.

Sign in / Sign up

Export Citation Format

Share Document