• Title, Summary, Keyword: absolute rotary encoder

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Design and Development of a Novel High Resolution Absolute Rotary Encoder System Based on Affine n-digit N-ary Gray Code

  • Paul, Sarbajit;Chang, Junghwan
    • Journal of Electrical Engineering and Technology
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    • v.13 no.2
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    • pp.943-952
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    • 2018
  • This paper presents a new type of absolute rotary encoder system based on the affine n-digit N-ary gray code. A brief comparison of the existing encoder systems is carried out in terms of resolution, encoding and decoding principles and number of sensor heads needed. Using the proposed method, two different types of encoder disks are designed, namely, color-coded disk and grayscale coded disk. The designed coded disk pattern is used to manufacture 3 digit 3 ary and 2 digit 5 ary grayscale coded disks respectively. The manufactured disk is used with the light emitter and photodetector assembly to design the entire encode system. Experimental analysis is done on the designed prototype with LabVIEW platform for data acquisition. A comparison of the designed system is done with the traditional binary gray code encoder system in terms of resolution, disk diameter, number of tracks and data acquisition system. The resolution of the manufactured system is 3 times higher than the conventional system. Also, for a 5 digit 5 ary coded encoder system, a resolution approximately 100 times better than the conventional binary system can be achieved. In general, the proposed encoder system gives $(N/2)^n$ times better resolution compared with the traditional gray coded disk. The miniaturization in diameter of the coded disk can be achieved compared to the conventional binary systems.

Development of Proportional Valve Actuator Controller for Industrial Site (산업용 밸브 액추에이터 비례제어 컨트롤러 개발)

  • Park, Han Young;Kim, Jin Young;Ahn, Sung Soo;Kang, Joonhee
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.5
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    • pp.269-274
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    • 2013
  • To proportionally control the electronic valve position of the actuator, we designed and fabricated PCU, CPT, and rotary absolute optical encoder for the detection of absolute angular position in the actuator. We also designed and constructed the test system by using DAQ hardware and Labview. We designed PCU to convert 1-5 V, 0-5 V, 0-10 V, 2-10 V voltage signals and 4-20 mA current signals to the voltage signals in the common 0.5-2.5 V range. We designed CPT to output 4-20 mA current signals corresponding to the valve positions based on the PWM signal input from the MCU. We also designed 20 bit optical encoder by using infrared LED and infrared transistor and made the serial communication with the main board possible. When we tested PCU and CPT with DAQ hardware and Labview software, they operated correctly with the small errors within ${\pm}0.003$ V and ${\pm}0.01$ mA, respectively, showing that our actuator has the excellent performance to employ as the industrial proportional-valve-actuator. The resolution of the encoder was $11.25^{\circ}$ and the maximum revolution to detect was 32,768.

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.

RVDT Phase Error Compensation for Absolute Displacement Measurement (절대 변위 측정용 RVDT의 위상 오차 보상)

  • Shin Dong-Yun;Yang Yoon-Gi;Lee Chang-Su
    • Journal of Institute of Control, Robotics and Systems
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    • v.12 no.7
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    • pp.658-665
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    • 2006
  • RVDT is a transducer that presents rotary phase angle according to the displacement of eccentric rotor such as press machine. However a study on the phase error of RVDT that affects precision is not enough. This paper analyzes RVDT phase error and obtains compensation curves with serial or parallel resistance through simulation. First, error compensation procedure that analyses errors due to the unbalance of reference inductances of each pole and uses parallel resistance as a compensation is proposed. Second, error compensation procedure due to the amplitude unbalance of the sensor driving currents is examined by serial compensation resistance. Experimentally, we got stable RVDT with phase error under $1^{\circ}$ by the proposed method.