• Title/Summary/Keyword: Temperature Error Compensation

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The Bias Drift Due to Fiber Coil Temperature Variation and the Temperature Compensation in Fiber Optic Gyroscope (광섬유자이로의 고리 온도변화에 의한 바이어스 특성 및 온도 보상)

  • Jo, Min-Sik;Chong, Kyoung-Ho;Do, Jae-Chul;Choi, Woo-Seok;Song, Ki-Won;Kang, Su-Bong;Shin, Won-Chul
    • Journal of the Korea Institute of Military Science and Technology
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    • v.12 no.2
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    • pp.222-227
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    • 2009
  • The bias characteristics due to the changes of temperature and temperature gradient of fiber coil are investigated in fiber-optic gyroscope. The bias performance is degraded with the changes of temperature and temperature gradient of fiber coil. The temperature compensation using both the temperature-dependent bias measurement and the temperature-induced error model of fiber-optic gyroscope improves the bias stability about 3 times as much as the uncompensated original case, which leads to very stable bias performance over the temperature range from $-35^{\circ}C$ to $+77^{\circ}C$.

Temperature Compensation Algorithm of Nondispersive Infrared (NDIR) Gas Sensor (비분산 적외선 가스센서의 온도보상 알고리즘)

  • Park, Jong-Seon;Yi, Seung-Hwan
    • Journal of the Korean Institute of Gas
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    • v.15 no.4
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    • pp.51-55
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    • 2011
  • This paper describes the temperature compensation algorithm using thermopile detector for nondispersive infrared methane gas sensor. From the output voltage of thermistor that is attached onto the infrared detector, the ambient temperature was extracted. The effects of temperatures on the properties of sensor module (the characteristics of narrow bandpass filter, optical cavity and infrared lamp, and gas absorption coefficient times optical path length) have been introduced in order to implement the temperature compensation algorithm. Even though the measurement error of developed sensor module was in the range of $\pm$ 1,500 ppm, after programming the temperature compensation algorithm, the developed sensor module shows a high accuracy less than +180 ppm error within $20^{\circ}C$ temperature variation.

The enhancement of 3-dimensional positioning accuracy by measuring error factors for CNC machine tools (공작기계의 오차요소 측정을 통한 3차원 위치정밀도 향상)

  • 손진욱;서석환;정세용;이응석;위현곤
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.260-265
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    • 1994
  • Efforts have been devoted to developing rapid and accurate methods for measuring the errors of machine tools. The method os measurement and calibration of machine tool errors should be general and efficient. The objective of this study is to show in detail the full sequence from the measurement of errors factors to the verification of the positioning accuracy after compensation for the volumetric error. In this paper, we described the steps in measuring the volumetric error parameters, a general error model composed of error parameters, temperature, and the desired position. The validity of the error calibration methods proposed in this paper was tested using a vertical 3-axis CNC machine with a laser interferometer and a ball bar.

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A Study on Possibility of Improvement of MIR Brightness Temperature Bias Error of KOMPSAT-3A Using GEOKOMPSAT-2A (천리안2A호를 이용한 다목적실용위성3A호 중적외선 밝기 온도 편향오차 개선 가능성 연구)

  • Kim, HeeSeob
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.12
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    • pp.977-985
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    • 2020
  • KOMPSAT-3A launched in 2015 provides Middle InfraRed(MIR) images with 3.3~5.2㎛. Though the satellite provide high resolution images for estimating bright temperature of ground objects, it is different from existing satellites developed for natural science purposes. An atmospheric compensation process is essential in order to estimate the surface brightness temperature from a single channel MIR image of KOMPSAT-3A. However, even after the atmospheric compensation process, there is a brightness temperature error due to various factors. In this paper, we analyzed the cause of the brightness temperature estimation error by tracking signal flow from camera physical characteristics to image processing. Also, we study on possibility of improvement of MIR brightness temperature bias error of KOMPSAT-3A using GEOKOMPSAT-2A. After bias compensation of a real nighttime image with a large bias error, it was confirmed that the surface brightness temperature of KOMPSAT-3A and GEOKOMPSAT-2A have correlation. We expect that the GEOKOMPSAT-2A images will be helpful to improve MIR brightness temperature bias error of KOMPSAT-3A.

Controller design to diminish oscillation and steady state error in water temperature systems with drive delay

  • Nakamura, Masatoshi
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10b
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    • pp.1888-1893
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    • 1991
  • Systematic design of a controller for a water temperature system was considered, with the intention of devising an accurate control experiment. The results of an experiment using a water temperature system based on the pole placement regulator showed water temperature oscillation and steady state error. This paper proposed a. method for eliminating both the oscillation and the steady state error. The oscillation was eliminated by a drive delay compensation technique, in which a future state value of the system was predicted through a real time computer simulation. The steady state error was eliminated by an steady state error correction technique, in which an actual steady state heatrate in the system model was replaced by an imaginary heatrate. By combining these two techniques, we obtained an experimental result for water temperature control of 0.01 (.deg. C) accuracy. Furthermore, the proposed method was evaluated relatively by comparing the experimental results using several other methods and proved to be the most accurate and convenient control method for the delay system.

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Modeling and Compensatory Control of Thermal Error for the Machine Orgin of Machine Tools (공작기계 원점 열변형오차의 모델링 및 보상제어)

  • 정성종
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.4
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    • pp.19-28
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    • 1999
  • In order to control thermal deformation of the machine origin of machine tools a empirical model and a compensation system have been developed, Prior to empirical modeling the volumetric error considering shape errors and joint errors of slides is formulated through the homogeneous transformation matrix (HTM) and kinematic chain. Simulation results of the HTM method show that the thermal error of the machine origin is more critical than position-dependent errors. In order to make a stable and effective software error compensation system the GMDH (Group Method of Data Handling) models are constructed to estimate the thermal deformation of the machine origin by measuring deformation data and temperature data. A test bar and gap sensors are used to measure the deformation data. In order to compensate the estimated error the work origin shift method is developed by implementing a digital I/O interface board between a CNC controller and an IBM PC. The method shifts the work origin as much as the amounts which are calculated by the pre-established thermal error model. The experiment results for a vertical machining center show that the thermal deformation of the machine origin is reduced within $\pm$5$mu extrm{m}$.

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Quantification of Thermal Shock in a Piezoelectric Pressure Transducer (압전식 압력센서에서 발생하는 열충격 효과 정량화)

  • Lee, Seok-Hwan;Choi, Wook;Bae, Choong-Sik
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.5
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    • pp.96-103
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    • 2005
  • One of the major problems limiting the accuracy of piezoelectric transducers fur cylinder pressure measurements in an internal combustion (IC) engine is the thermal shock. Thermal shock is generated from the temperature variation during the cycle. This temperature variation results in contraction and expansion of the diaphragm and consequently changes the force acting on the quartz in the pressure transducer An empirical equation for compensation of the thermal shock error was derived from consideration of the diaphragm thermal deformation and actual pressure data. The result indicate that the thermal shock equation provides reliable correction based on known surface temperature swing.

Portable thermocouple thermometer on the nonlinearity compensation (비선형 특성을 보정한 휴대용 열전대 온도계)

  • Kim, Seong-Kuk;Song, Jae-Won
    • Journal of Sensor Science and Technology
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    • v.4 no.1
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    • pp.21-28
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    • 1995
  • A portable type K thermocouple thermometer is designed and fabricated to compensate the linearity to the high temperature $1000^{\circ}C$. The problems to be solved, which use a thermocouple thermometer are the compensation of the nonlinearity characters and reference compensation. The nonlinear character of the thermocouple is compensated, using an EPROM, and the reference compensation done using an IC AD595A. Before this compensation, there was the maximum error of $23.6^{\circ}C$(2.69%) at $876^{\circ}C$. However the results measured by the portable type K thermocouple thermometer fabricated show the character of the error of ${\pm}2^{\circ}C$(0.2%) in the range of the total temperature. This character satisfies the precision specifications of the type K thermal sensors in the range available $1000^{\circ}C$, which can be measured by the use of type K thermocouples. Therefore the portable type K thermocouple thermometer fabricated can be comparatively exactly used for the wide range of temperature of interest. Then this technique of compensating the nonlinear characters can be applied to the other kinds of thermal sensor compensation.

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Temperature Compensation of Hot-film Flow Sensor (박막 히터형 유량센서의 온도보상)

  • Kim, Hyung-Pyo
    • Journal of Sensor Science and Technology
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    • v.9 no.4
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    • pp.268-273
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    • 2000
  • This paper represents a hot-film flow sensor which is compensated by a noble temperature compensation method using the initial unbalanced voltage. The resistance value of the sensor is determined by using the graph of the initial unbalanced voltage of an open-loop circuit against the air temperature. The compensation is accomplished by applying the unbalanced ratio of the resistors in the Wheastone bridge circuit. In the range of air temperature of $-20^{\circ}C{\sim}120^{\circ}C$, the error is about ${\pm}1%$.

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Proposal for a Wavelength-Independent Optical Sensor Based on an Asymmetric Mach-Zehnder Interferometer

  • Luo, Yanxia;Yin, Rui;Ji, Wei;Huang, Qingjie;Gong, Zisu;Li, Jingyao
    • Current Optics and Photonics
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    • v.4 no.6
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    • pp.558-565
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    • 2020
  • A wavelength-independent optical sensor based on an asymmetric Mach-Zehnder interferometer (AMZI) is proposed. The optical sensor based on an AMZI is very sensitive to wavelength, and wavelength drift will lead to measurement error. The optical sensor is compensated to reduce its dependence on wavelength. The insensitivity of the optical sensor to wavelength mainly depends on the compensation structure, which is composed of an AMZI cascaded with another AMZI and can compensate the wavelength drift. The influence of wavelength drift on the optical sensor can be counteracted by carefully designing the size parameters of the compensation structure. When the wavelength changes from 1549.9 nm to 1550.1 nm, the error after compensation can be lower than 0.066%. Furthermore, the effect of fabrication tolerance on compensation results is analyzed. The proposed compensation method can also be used to compensate the drift of other parameters such as temperature, and can be applied to the compensation of other interference-based optical devices.