• Title, Summary, Keyword: RVDT (Rotary Variable Differential Transformer)

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FPGA Implementation of Resolver-based Absolute Position Sensor Driver (레졸버 기반의 절대위치 검출 센서 드라이버의 FPGA 구현)

  • Jeon, Ji-Hye;Shin, Dong-Yun;Yang, Yoon-Gi;Hwang, Jin-Kwon;Lee, Chang-Su
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.10
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    • pp.970-977
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    • 2007
  • Absolute position detector which is one of the major equipment in the field of factory automation, not only perceives the absolute position of the rotary machine but also outputs switch data according to the given angle. Absolute position detector is composed of sensor module and its controller. In this paper, a sensor driver is implemented using FPGA with VHDL. This chip has a less form factor than conventional circuit. A test shows reliable precision within THD(total harmonic distortion) of 0.2% which can be applicable commercially. Also, FPGA-based phase error compensation methods were newly discussed. In the future, more research will be conducted to enhance the precision by the introduction of 3-phase transformer.

FPGA Implementation of RVDT Digital Signal Conditioner with Phase Auto-Correction based on DSP (RVDT용 DSP 기반 위상 자동보정 디지털 신호처리기 FPGA 구현)

  • Kim, Sung-mi;Seo, Yeon-ho;Jin, Yu-rin;Lee, Min-woong;Cho, Seong-ik;Lee, Jong-yeol
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.21 no.6
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    • pp.1061-1068
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    • 2017
  • A RVDT is a sensor that measures angular displacement and the output signal of RVDT is a DSBSC-AM signal. For this reason, a DSBSC-AM demodulation processor is required to determine the angular displacement from the output signal. In this paper, DADC(Digital Angle to DC) which extracts the angular displacement from the output signal of a RVDT is implemented based-on modified Costas Loop usually used in the demodulation of DSBSC-AM signal by using FPGA. DADC can used with both 4-wire and 5-wire RVDTs and can exactly compensate the phase difference between the input excitation and output signals of a RVDT unlike the conventional analog RVDT signal conditioners which require external components. Since digital signal processing technique that can enhance the linearity is exploited, DADC shows 0.035% linearity error, which is smaller than 0.005% that of a conventional analog signal conditioner. The DADC are tested in an integrated experimental environment which includes a commercial RVDT sensor, ADC and an analog output block.

An Improved Phase Error Compensation for an Absolute Position Detector using Table Method (테이블 방법을 이용한 절대위치 검출기에 대한 개선된 위상 오차 보상)

  • Ahn, Ki-Ho;Kim, See-Hyun;Yang, Yoon-Gi;Lee, Chang-Su
    • Journal of Institute of Control, Robotics and Systems
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    • v.16 no.10
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    • pp.975-981
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    • 2010
  • Existing error compensation method of industrial electronic absolute displacement detector only depends on skilled engineers. This paper proposes a new table method in order to automatize error compensation. An waveform changes according to the parallel resistance for each pole were tabularized and four waveforms were superimposed to minimize total phase error. These process was verified using simulink. As a result of applying proposed method to the real sensor, peak to peak error was reduced from $3.428^{\circ}$ to $0.879^{\circ}$. In this case, compensation resistance is $4.7k\Omega$ in B pole and $20k\Omega$ in C pole. This compensation rate is comparable to skilled engineers, and it takes 0.8 second which is far shorter than 15 minutes when expert does.