Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
권호 표지
DOI QR코드

DOI QR Code

A Switching Notch Filter for Reducing the Torque Ripple Caused by a Harmonic Drive in a Joint Torque Sensor

하모닉 드라이브의 토크리플 감소를 위한 조인트 토크센서용 스위칭 노치필터

  • Received : 2010.08.10
  • Accepted : 2011.04.26
  • Published : 2011.07.01
Download PDF
⟨ Previous Next ⟩

Abstract

Harmonic drives have been widely used in combination with joint torque sensors in order to facilitate accurate manipulator control. A harmonic drive causes a torque ripple because of its structural characteristics, and this torque ripple tends to deteriorate the performance of a controller or observer that uses torque sensors. This paper proposes a switching notch filter for reducing the torque ripple caused by a harmonic drive in a joint torque sensor; the functioning of this filter is based on the relationship between the frequency components of the torque ripple and the rotational velocity of the harmonic drive. The proposed switching notch filter is advantageous in that it requires less computational load and does not necessitate additional circuits or structures. Various experiments demonstrate that the proposed filter has good filtering performance, fast response, and good switching stability.

로봇 머니퓰레이터의 정밀한 제어를 위하여 하모닉 드라이브와 조인트 토크센서가 널리 사용되고 있다. 하모닉 드라이브는 구조적 특징으로 인하여 토크리플을 발생시키는데, 토크센서와 하모닉 드라이브가 직결된 경우에 토크리플은 토크센서에 전달되어 토크센서를 사용하는 제어기나 관측기의 성능을 저해한다. 본 논문에서는 토크리플과 하모닉 드라이브 속도의 관계를 도출하고, 이를 토대로 토크리플을 효과적으로 감쇄시키는 스위칭 노치필터를 제안한다. 제안된 스위칭 노치필터는 기존에 제시되었던 이론에 비하여 직관적이고, 추가적인 회로부나 기구부 구성이 필요 없으며, 연산량이 적은 장점이 있다. 또한 다양한 실험을 통하여 스위칭 노치필터의 필터링 성능, 빠른 응답속도와 스위칭 안정성을 검증하였다.

Keywords

References

  1. Timothy, D. T. and Warren, P. S., 1996, "A Nonlinear Model of Harmonic Drive Gear Transmission," IEEE Int. Conf. on Robotics and Automation, Vol. 12, No. 3, pp. 368-374. https://doi.org/10.1109/70.499819
  2. Richard, D., Fathi, H. G. and Prasanna, S. G., 2003, "A New Dynamic Model of Hysteresis in Harmonic Drives," IEEE Trans. on Industrial electronics, Vol. 50, No. 6, pp. 1165-1171. https://doi.org/10.1109/TIE.2003.819661
  3. Ivan, G., Tamotsu, N. and Masashi, H., 2001, "Ripple Compensation for Torque Sensors Built into Harmonic Drives," IEEE Trans. on instrumentation and measurement, Vol. 50, No. 1, pp. 117-122. https://doi.org/10.1109/19.903888
  4. Jonathon, W. S. and Richard, F., 2006, "Improved Torque Fidelity in Harmonic Drive Sensors Through the Union of Two Existing Strategies," IEEE/ASME Trans. on mechatronics, Vol. 11, No. 4, pp. 457-461. https://doi.org/10.1109/TMECH.2006.878540
  5. Hamid, D. T. and Belanger P. R., 1998, "Torque Ripple and Misalignment Torque Compensation for the Built-In Torque Sensor of Harmonic Drive Systems," IEEE trans. on instrumentation and measurement, Vol. 47, No. 1, pp. 309-315. https://doi.org/10.1109/19.728840
  6. Thede, L., 2004, Practical Analog and Digital Filter Design, Artech House, Boston, pp. 98-103.
  7. Zhen Y. Z., Masayoshi. T. and Satoru. I., 1993, "Fuzzy Gain Scheduling of PID Controllers," IEEE Trans. on Systems, Man, and Cybernetics, Vol. 23, No. 5, pp. 1392-1398. https://doi.org/10.1109/21.260670
  8. Hespanha, J. P., Liberzon, D. and Morse, A. S., 2001, "Multiple Model Adaptive Control, Part 2: Switching," Int. Journal of Roboust Nonlinear Control, No. 11, pp. 479-496.
  9. Nam, K. H. and Song, J.-B., 2009, "Joint Torque Sensor Based on Hub-Spoke Type Structure for a Service Robot," Conf. on the KSME, pp. 247-249.