• Journal of Institute of Control, Robotics and Systems
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• v.6 no.1
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• pp.51-56
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• 2000

This paper presents the characteristics of the dynamic response and calibration technique on a linear variable differential transformer(LVDT). The linear error of the LVDT was proven $\pm$1% in the static calibration and $\pm$0.5% in the dynamic calibration. In this paper, the linearity error generated in the static and dynamic state of the core movement can be eliminated using the correction algorithem of the static and dynamic state derived from the least square linear approximation for the nonlinearity of the curves of direct data fitting and Lagrange polynomials. With the static and dynamic calibration method, the calibration accuracy of the LVDT can be reduced to within $\pm{0.5%.}$.

• Transactions on Control, Automation and Systems Engineering
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• v.2 no.3
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• pp.214-219
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• 2000

This paper presents a recoil and counter recoil motion measurement system using linear variable differential transformers (LVDT). The output of the LVDT is obtained from the differential voltage of the secondary transformers. Since a transducer core is attached to the motion body, the output is directly proportional to the movement length of the core. Displacement, velocity and acceleration are measured from the LVDT. With a comparison between the measurement result and the reference value obtained by the highly accurate Vernier calipers, it is proved that the measurement system with the LVDT is applicable to the test of the moving part of the mechanism with better accuracy.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.871-872
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• 2011

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.3
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• pp.11-22
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• 2012

In this study, problems of RTK (Real Time Kinematic)-GPS (Global Positioning System) and an accelerometer sensor when applied to structures were experimentally identified through a comparison between results of the displacement measurement using the RTK-GPS, the accelerometer, and LVDT (Linear variable differential transformer). Integrated displacement was calculated by the improved RTK-GPS and accelerometer on the frequency of observation and positioning accuracy. This integrated displacement was also compared with that of LVDT to check the validity of application and feasibility.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.60-62
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• 1994

In this paper, the LVDT with compensating secondary coil and secondary current boost circuit is proposed. The LVDT was experiment with a test device, and analyzed with numerical method (FEM), It is shown that the LVDT has a good linearities for the measurement of the displacement and position, etc..

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.1
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• pp.57-64
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• 2010

Measurements of deflection in load testing of structures are typically obtained with contact instrumentations such as LVDT (Linear-Variable Differential Transformer). LVDT only measure 1-dimensional deformation and in destructive testing is damage to instrumentation, thus prohibiting deflection when the beam is close to failure. Measurements of deflection using non-metric digital cameras are useful for load testing because there are very little cost or beam failure except for cheap targets and measurements in 3-dimensional deflection can obtained rapidly. In this research, deflection of concrete beam was measured using Nikon D80 DSLR camera, and the accuracy was evaluated with comparing the outputs to the LVDT measurements. The results show that the accuracy of terrestrial photogrammetric measurements are ${\pm}$0.5mm, ${\pm}$0.5mm, ${\pm}$0.6mm for each X, Y, Z directions, and the RMSE of comparison to LVDT is ${\pm}$0.57mm.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.1
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• pp.50-50
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• 2000

• Journal of the Korean Society of Industry Convergence
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• v.19 no.3
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• pp.160-166
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• 2016

This study proposes the development and performance evaluation of electronic proportional control valve having an LVDT. The electronic proportional control valve is composed of hydraulic valve, proportional solenoid and controller. LVDT is to reduce the steady state error for the reference input of the controller by the feedback signal to detect the displacement of the spool. Designed LVDT is applied to the common proportional valve. In order to evaluate the performance of the developed valve, the hydraulic test equipment was developed and flow tests were carried out. From experimental results, it was proved that the hysteresis was less than 1% based on the maximum flow rate.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.9
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• pp.11-19
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• 2021

Linear variable differential transformer (LVDT) is a displacement sensor and is commonly used owing to its wide measurement range, excellent linearity, high sensitivity, and precision. To improve the output characteristics of LVDT, a few studies have been conducted to analyze the output using a theoretical method or a finite element method. However, the material properties of the core and the electromagnetic force acting on the core were not considered in the previous studies. In this study, a finite element analysis model was proposed considering the characteristics of the LVDT composed of coils, core, magnetic shell and electric circuit, and the core displacement. Using the proposed model, changes in sensitivity and linear region of LVDT according to changes in process and material parameters were analyzed. The outputs of the LVDT model were compared with those of the theoretical analysis, and then, the proposed analysis model was validated. When the electrical conductivity of the core was high and the relative magnetic permeability was low, the decrease in sensitivity was large. Additionally, an increase in the frequency of the power led to further decrease in sensitivity. The electromagnetic force applied on the core increased as the voltage increased, the frequency decreased, and the core displacement increased.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.1 s.24
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• pp.89-98
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• 2006

This paper describes signal attenuation characteristics as splicing the output on LVDT for stability and reliability of switching mechanism, which is developed to use common signal between FLCC and EDFLCC, on T-50 aircraft. The method of test is classified a Pspice simulation and an actual hardware evaluation. The difference of error margin for two methods is 10times, the latter higher. The result in this experiment shows that the signal attenuation as splicing the output on LVDT doesn't affect and the static error margin is 53% for develope the EDFLCC.