• Title/Summary/Keyword: LVDT (Linear Variable Differential Transformer)

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An Implementation of High-precision Three-phase Linear Absolute Position Sensor (고정도 3상 직선형 절대 위치 센서의 구현)

  • Lee, Chang Su
    • Journal of IKEEE
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    • v.19 no.3
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    • pp.335-341
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    • 2015
  • Recently a demand for high precision absolute position transducer is increasing in order to control thickness in steel industry. LVDT (linear variable differential transformer) is widely used to measure the absolute position in the linearly moving cylinder under poor factory environment. In this paper we implement the three phase LVDT with a high resolution of one micron and L/D (LVDT to digital) converter. First we designed U, V, and W three phase signaling using FPGA. Second a pulse output algorithm is designed for position information with A and B phase waveforms. Finally the performance is compared with previous sensors. Experiments show that the linearity deviation error is 0.009788 [mm] and the average sinusoidal THD is 0.0751%, which means 2.2% and 33% more improved result than the previous sensors respectively.

Displacement Measurement Algorithm Based on Signal Mapping in LVDT Structure (LVDT 구조를 이용한 신호 매핑 기반의 변위측정 알고리즘)

  • Son, Jin-Ho;Cho, Sang-Bock
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.48 no.12
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    • pp.97-102
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    • 2011
  • We propose a novel displacement measurement method in the LVDT (Linear Variable Differential Transformer) structure. This proposed algorithm is independent of coil pattern, which may be implemented to PCB, or transformer component, because it is based on the signal-mapping method. we have manufactured several boards which have different coil patterns and our algorithm is ported into TMS320F2812 of TI DSP chipset. The output signal has high accuracy and high stability although PCB coil pattern are coarse.

EFFECT OF FIBER DIRECTION ON THE POLYMERIZATION SHRINKAGE OF FIBER-REINFORCED COMPOSITES (섬유 보강 복합레진의 섬유 방향이 중합수축에 미치는 영향)

  • Yom, Joong-Won;Lee, In-Bog
    • Restorative Dentistry and Endodontics
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    • v.34 no.4
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    • pp.364-370
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    • 2009
  • The aim of this study was to evaluate the effect of fiber direction on the polymerization shrinkage of fiber-reinforced composite. The disc-shaped flowable composite specimens (d = 10 mm, h = 2 mm, Aeliteflo A2, Bisco, Inc., IL, USA) with or without glass fiber bundle (X-80821P Glass Fiber, Bisco, Inc., IL, USA) inside were prepared, and the longitudinal and transversal polymerization shrinkage of the specimens on radial plane were measured with strain gages (Linear S-series 350${\Omega}$, CAS, Seoul, Korea). In order to measure the free polymerization shrinkage of the flowable composite itself, the disc-shaped specimens (d = 7 mm, h = 1 mm) without fiber were prepared, and the axial shrinkage was measured with an LVDT (linear variable differential transformer) displacement sensor. The cross-section of the polymerized specimens was observed with a scanning electron microscope to examine the arrangement of the fiber bundle in composite. The mean polymerization shrinkage value of each specimen group was analyzed with ANOVA and Scheffe post-hoc test (${\alpha}$=0.05). The radial polymerization shrinkage of fiber-reinforced composite was decreased in the longitudinal direction of fiber, but increased in the transversal direction of fiber (p<0.05). We can conclude that the polymerization shrinkage of fiber-reinforced composite splint or restoratives is dependent on the direction of fiber.

A Study on the out-diameter measuring machine by the LVDT sensors (LVDT 센서를 이용한 외경 측정 방안에 대한 연구)

  • Hwang J.H.;Roh J.H.;Park Ki-Hong
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.291-292
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    • 2006
  • Currently A demand of high precision workpiece is increasing in industry. At present, roundness measuring machine using Air bearing, coordinate measuring machine that are used from measurement station. but these machines will not be able to apply to In-line process. because of like these machine's price are very expensive and measurement time is long. also, the complexity of conventional roundness measurement method based on fourier transform, it makes difficult to development analysis program. This work present new architecture of a Out-diameter measuring system fur analysis of roundness of product. In this system, the influence of table motion errors is minimize by using two LVDT sensor and knife edge contact tip. We are produce a test machine and make an experimenter on Out-diameter of test bearing. The measurement result compared with roundness measuring machine.

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Measuring Inside Diameter with Electronic Micrometer (전기 마이크로미터를 이용한 내경측정)

  • 이헌민;배영주;이만형
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.491-494
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    • 1995
  • In this study, we presented a system to measure inside diameters of parts of compressor. This system solved problems of air micrometer and improved measurement accuracy by using linear variable differential transformer. The system was designed for production line which require accurate and reliable measuring system. And the system is easier and faster to use than air micrometer and can be applied various measuring area.

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Solvent-induced Expansion & Shrinkage of Demineralized Dentin Matrix

  • Lee, Kwang-Won
    • Proceedings of the KACD Conference
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    • 2001.11a
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    • pp.580-580
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    • 2001
  • Before resin composites can serve as durable substitutes for amalgam restorations, the adhesive system used to retain them and add to seal dentin must be improved. The recent observations, using the newly developed LVDT (linear variable differential transformer) probe, that all commercial bonding systems cause a collapse of the demineralized dentin matrix, simulated a re-evaluation of the effects of these formulations on the matrix. The experiment was begun by examining solvents such as water-HEMA mixtures. These produced the same shrinkages as did the complete formulations.(omitted)

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Development of Micro Displacement Extensometer for Environmental Fatigue Test in a High Temperature and High Pressure Autoclave (고온고압 환경피로실험 오토클래이브 내부용 미소변위 측정장치 개발)

  • Jeong, Ill-Seok;Ha, Gak-Hyun;Kim, Tae-Ryong;Jeon, Hyun-Ik;Kim, Young-Sin
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.368-371
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    • 2008
  • An extensometer system to measure strain and displacement of cylindrical fatigue specimen in a autoclave of high temperature and high pressure environment has been developed by KEPRI. The extensometer reads the displacement caused by fatigue loads at the target length of the specimen installed inside the autoclave. The performance of the extensometer were tested at 15MPa, $315^{\circ}C$ of a operating pressurized water reactor. Two LVDT's of magnet type were connected to the extensometer and used for converting the fatigue displacement to electronic signal. The device is being used for developing environmental fatigue curve of CF8M cast austenitic stainless steel (CASS) in the test condition of low cycle and low strain. This paper introduces the background and results of the development.

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A Study on the Universal Outer Diameter Measurement Module using LVDT (LVDT를 이용한 범용 외경측정 모듈에 관한 연구)

  • Lee, Neung-Gu;Kwac, Lee-Ku;Kim, Hong-Gun
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.16 no.3
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    • pp.100-106
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    • 2017
  • A universal outer diameter measurement module was developed using a linear variable differential transformer (LVDT). This outer diameter measurement module enables simultaneous measurement of outer diameter, displacement, and perpendicularity of bench-type high-precision products by combining analogue and digital measurement principles with mechanically precise and fine adjustment functions. The developed module showed a performance of 0.001mm in measurement resolution, 0.001mm in measurement accuracy, reference surface abrasion lower than Ra 0.1864, and measurement stability of 0.002mm. Therefore, we have acquired domestic measurement technology to improve productivity by securing technical competitiveness for universal diameter measurement technology, lower production costs through import substitution, and increased quality of products with more precise measurement technology. Furthermore, a substitution effect is expected for expensive import measurement system equipment used in production, research, and inspection sites in industries that produce precision processing products such as automobile and machine components.

Design of Capacitive Sensor for Measuring the Position of the Piston in Hydraulic Cylinder (유압 실린더 내 피스톤 위치측정을 위한 정전용량 센서 설계)

  • Lee, Soeng-hwi;Lee, Jae-gun;Kang, Yong-joo;Hong, Ic-pyo
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.05a
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    • pp.509-512
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    • 2015
  • In this paper, several capacitive sensors for measuring the position of the piston in hydraulic cylinder was studied and designed. The inductive LVDT sensor has been widely used to measure the position of the piston because of its high accuracy, but this type of sensor is very expensive and has difficulty in use because of its complexity. To overcome these disadvantages, we studied the optimized non-contact capacitive sensors and designed several capacitive sensors for accurate measuring the location of piston in hydraulic cylinder. The proposed capacitive sensor has the possibility of practical use for hydraulic cylinder through experiments.

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Performance Analysis of Smart Automatic Jack-Up System Using the Pairwise Comparison Matrix Analysis Method (쌍대비교행렬 분석 기법을 적용한 스마트 자동 인상 시스템의 성능 분석)

  • Kim, Sung-Jo;Ji, Yongsoo;Kim, Bongsik;Han, Tong-Seok
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.35 no.1
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    • pp.9-14
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    • 2022
  • In this study, a smart jack-up system was developed to prevent safety accidents by performing risk analysis when a structure is lifted for maintenance. A quantitative risk analysis program that can analyze the risk using the pairwise comparison matrix analysis method was developed. The risk was analyzed in real-time for the lifting structure by connecting the program with an automatic jack-up system. Displacements were measured by the IR sensor among the components of the automatic jack-up system, and the displacements were provided to the quantitative risk analysis program. To confirm the performance of the smart automatic jack-up system, experiments were conducted on bridge and risk analysis was performed when a superstructure was lifted. A linear variable differential transformer (LVDT) was also installed on the bridge to verify the performance of the smart automatic jack-up system. The maximum displacements were measured using the devices, and the declinations were compared. The performance of the simultaneous operation of the jack-up device was verified by the analysis of variance (ANOVA).