A Study on Convergence Property of Iterative Learning Control

반복 학습 제어의 수렴 특성에 관한 연구

  • 박광현 (한국과학기술원 인간친화 복사 로봇시스템 연구센터) ;
  • 변증남 (한국과학기술원 전자전산학과)
  • Published : 2001.08.31

Abstract

In this paper, we study the convergence property of iterative learning control (ILC). First, we present a new method to prove the convergence of ILC using sup-norm. Then, we propose a new type of ILC algorithm adopting intervalized learning scheme and show that the monotone convergence of the output error can be obtained for a given time interval when the proposed ILC algorithm is applied to a class of linear dynamic systems. We also show that the divided time interval is affected from the learning gain and that convergence speed of the proposed learning scheme can be increased by choosing the appropriate learning gain. To show the effectiveness of the proposed algorithm, two numerical examples are given.

본 논문에서는 반복 학습 제어의 수렴 특성에 대해 다룬다. 우선, 기존의 ${\lambda}$-노옴을 사용하여 반복 학습 법칙의 수렴성을 증명한 것과는 달리 상한노옴(sup-norm)을 사용한 수렴성 증명방법을 보인다. 또한, 구간화된 학습 방법을 사용한 반복 학습 법칙을 제안하고, 임의의 시간구간에 대해 상한노옴 관점에서 출력 오차의 단조감소적 수렴 특성을 얻을 수 있음을 보인다. 마지막으로, 제안한 구간화된 학습 방법에서의 나누어진 시간 구간이 학습 이득값에 의해 영향을 받는다는 것을 보이고, 적절한 학습 이득값을 선택함에 따라 학습 속도가 증가함을 보인다. 제안한 반복 학습 법칙의 유효성을 보이기 위하여 두 가지 수치 예를 보인다.

Keywords

References

  1. S. Arimoto, S. Kawamura and F. Miyazaki, 'Bettering Operation of Robots by Learning,' Journal of Robotic System, 1(123), pp. 123-140, 1984 https://doi.org/10.1002/rob.4620010203
  2. H. S. Lee and Z. Dien, 'Robustness and Convergence of a PD-type Iterative Learning Controller,' Iterative Learning Control: Analysis, Design, lntegration and Applications, Edited by Z. Bien and J. -X. Xu, Kluwer Academic Publishers, Chapter 3, 1998
  3. S. Arimoto, T. Naniwa and H. Suzuki, 'Robustness of P-typc Learning Control with a Forgetting Factor for Robotic Motions,' Proceedings of the 29th IEEE Conference on Decision and Control, Honolulu, Hawaii, USA, pp. 2640-2645, 1990 https://doi.org/10.1109/CDC.1990.203457
  4. N. Amann, D. H. Owens, E. Rogers and A. Wahl, 'An $H_{\infty}$ Approach to Linear Iterative Learning Control Design,' International Journal of Adaptive Control and Signal Processing, 10(6), pp. 767-781, 1996 https://doi.org/10.1002/(SICI)1099-1115(199611)10:6<767::AID-ACS420>3.0.CO;2-L
  5. A. De Luca, G. Paesano and G. Ulivi, 'A Frequency-domain Approach to Learning Control: Implementation for a Robot Manipulator,' IEEE Control Systems, 39(1), pp. 1-10, 1992 https://doi.org/10.1109/41.121905
  6. H. -S. Lee and Z. Bien, 'Study on Robustness of Iterative Learning Control with Non-Zero Initial Error,' International Journal of Control, 64(3), pp. 345-359, 1995 https://doi.org/10.1080/00207179608921632
  7. K. H. Park, Z. Bien and D. -H. Hwang, 'Design of an Iterative Learning Controller for a Class of Linear Dynamic Systems with Time-delay,' lEE Proceedings - Part D, 145(6), pp. 507-512, 1998
  8. K. -H. Park, Z. Bien and D. -H. Hwang, 'A Study on the PID-type Iterative Learning Controller against Initial State Error,' International Journal of Systems Science, 30(1), pp. 49-59, 1999 https://doi.org/10.1080/002077299292669