Measurement equations and formulas

Author(s):  
Fenghui Lian ◽  
Qingchang Tan ◽  
Siyuan Liu

A method for measuring block thicknesses is proposed by the machine vision measurement. Equations of the measuring base plane and the light plane are formed by calibration. Then, the equation of the light strip image, that is, the image of the intersection between the base plane and light one, is established by the projection relation. Equation of the image of the light strip on the measured plane can be determined by the fitting. Since the light strip on the measuring base plane is parallel to one on the measured plane, the thickness of the measuring block is measured by using the two equations. The experiment evaluates the measurement accuracy of the measurement method and analyzes the influence of some factors on the measurement results.


Author(s):  
Qingjia Gao ◽  
Qiang Sun ◽  
Feng Qu ◽  
Jiang Wang ◽  
Xizhen Han ◽  
...  

Line-of-sight rate is the key parameter that enables inertial stabilized platforms to implement guidance laws successfully for target tracking or attacking. It is always obtained by experiments. In this article, a theoretical model of the line-of-sight rate is established for the first time, starting with the gimbal motion. The strategy to acquire line-of-sight rate is based on the servo control circuit. The measurement equations for line-of-sight rate are derived using a coordinate transformation. An error model is then obtained with the help of differentiation. The error of an inertial stabilized platform prototype is measured, showing that the line-of-sight rate error can be predicted accurately. Finally, a high-precision inertial stabilized platform is successfully designed and analyzed, with the accuracy of 0.06°/s and 0.37°/s when line-of-sight rates are set to 1.5°/s and 9°/s, respectively.


Author(s):  
S. G. Khan ◽  
◽  
L. K. Ibrayeva ◽  
N. V. Syabina ◽  
Z. M. Yuldashev ◽  
...  

To create conditions for the recognition of Kazakhstani certificates of conformity and the results of product tests, an assessment of measurement uncertainty is required. In this regard, there has been an increase in the practical application in Kazakhstan of the concept of measurement uncertainty. The authors developed a physical stand for a mobile complex designed to verify electromagnetic flowmeters at the place of operation. To obtain verification results, programs were developed to calculate the uncertainty of an electromagnetic flowmeters using the NI LabView software. In addition, a model for estimating the uncertainty of the relative error of flowmeters was proposed, and the measurement uncertainty was estimated using three methods: standard, Monte Carlo and Kragten. Finally, a comparative analysis was conducted on the results of the estimation of the uncertainty of the relative error of the industrial electromagnetic flowmeter. All methods give standard uncertainty values that do not exceed the acceptable range of relative error (± 1%). However, Monte Carlo method gives better results for sufficiently large number of simulations. No significant differences between the results obtained using standard and Kragten methods were discovered. The Kragten method is preferable in the absence of the need to calculate the sensitivity coefficients when calculating the total standard uncertainty, which is important for complex measurement equations.


2015 ◽  
Vol 12 ◽  
pp. 73-85 ◽  
Author(s):  
S.J. Perkins ◽  
P.C. Marais ◽  
J.T.L. Zwart ◽  
I. Natarajan ◽  
C. Tasse ◽  
...  

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