Journal of the Korean Society for Precision Engineering (한국정밀공학회지)

Korean Society for Precision Engineering (한국정밀공학회)
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Development of a High-Resolution Encoder System Using Dual Optical Encoders

이중 광학식 회전 엔코더 구조를 이용한 고정밀도 엔코더 시스템 개발

  • 이세한 (경남대학교 기계자동화공학부)
  • Published : 2007.09.01
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Abstract

An optical rotary encoder is easy to implement for automatic control applications. In particular, the output of the encoder has a digital form pulse, which is also easy to be connected to a popular digital controller. By using the encoder, there are various angular velocity detecting methods, M-, T-, and M/T-method. Each of them has a property of its own. They have common limitation that the angular velocity detection period is strongly subject to the destination velocity magnitude in case of ultimate low range. They have ultimate long detection period or cannot even detect angular velocity at near zero velocity. This paper proposes a dual encoder system with two encoders of normal resolution. The dual encoder system is able to keep detection period moderately at near zero velocity and even detects zero velocity within nominal period. It is useful for detecting velocity in case of changing rotational direction at which there occurs zero velocity. In this paper, various experimental results are shown for the dual encoder system validity.

Keywords

References

  1. Brown, R. H., Schneider, S. C. and Mulligan, M. G, 'Analysis of algorithms for velocity estimation from discrete position versus time data,' IEEE Trans, Ind. Electron., Vol. 39, Issue 1, pp. 11-19, 1992 https://doi.org/10.1109/41.121906
  2. Ohmae, T., Matsuda, T., Kamiyama, K. and Tachikawa, M., 'A microprocessor-controlled high-accuracy widerange speed regulator for motor drives,' IEEE Trans. Ind. Electron., Vol. IE-29, Issue 3, pp. 207-211, 1982
  3. Belanger, P. R., Dobrovolny, P., Helmy, A. and Zhang, X., 'Estimation of angular velocity and acceleration from shaft-encoder measurements,' Int. J. Robot. Res., Vol. 17, No. 11, pp. 1225-1233, 1998 https://doi.org/10.1177/027836499801701107
  4. Dunworth, A., 'Digital instrumentation for angular velocity and acceleration,' IEEE Trans. Instrum. Meas., Vol. IM-18, Issue 3, pp.132-138, 1969
  5. Saito, K., Kamiyama, K., Ohmae, T. and Matsuda, T., 'A microprocessor controlled speed regulator with instantaneous speed estimation for motor drives,' IEEE Trans. Ind. Electron., Vol. 35, Issue 1, pp. 95-99, 1988 https://doi.org/10.1109/41.3068
  6. Hori, Y., 'Robust and adaptive control of a servomotor using low precision shaft encoder,' IEEE IECON'93, pp. 73-78, 1993
  7. Lee, S. H., Lasky, T. A. and Velinksky, S. A., 'Improved velocity estimation for low-speed and transient regimes using low-Resolution Encoders,' IEEE/ASME Trans. Mechatron., Vol. 9, No.3, pp. 553-560,2004 https://doi.org/10.1109/TMECH.2004.835338
  8. Ishikawa, J. and Tomizuka, M., 'Pivot friction compensation using an accelerometer and a disturbance observer for hard disk drives,' IEEE/ASME Trans. Mechatron., Vol. 3, Issue 3, pp. 194-201, 1998 https://doi.org/10.1109/3516.712115
  9. Lee, S. H. and Song, J. B., 'Acceleration estimation for low-velocity and low-acceleration regions based on encoder position data,' IEEE/ASME Trans. Mechatron., Vol. 6, No.1, pp. 58-64,2001 https://doi.org/10.1109/3516.914392
  10. Kim, K. J. and Kim, Y. G, 'Fabrication of Optical Micro-Encoder Chips for Sub-Micron Displacement Measurements,' J. of the Korea Society for Precision Engineering, Vol. 16, No.2, pp. 74-81, 1999