Robust disturbance rejection for repetitive control systems with time-varying nonlinearities

Pan Yu, Kang Zhi Liu, Jinhua She, Min Wu*, Yosuke Nakanishi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)


This paper presents a disturbance-rejection method for a modified repetitive control system with a nonlinearity. Taking advantage of stable inversion, an improved equivalent-input-disturbance (EID) estimator that is more relaxed for system design is developed to estimate and cancel out the influence of the disturbance and nonlinearity in the low-frequency domain. The high-frequency influence is filtered owning to the low-pass nature of the linear part of the closed-loop system. To avoid the restrictive commutative condition and choose a Lyapunov function of a more general form, a new design algorithm, which takes into account the relation between the feedback control gains and the observer and improved EID estimator gains, is developed for the nonlinear system. Furthermore, comparisons with the generalized extended-state observer (GESO) and conventional EID methods are conducted. A clear relation between the developed estimator and the GESO is also clarified. Finally, simulations show the effectiveness and the advantage of the developed method.

Original languageEnglish
Pages (from-to)1597-1612
Number of pages16
JournalInternational Journal of Robust and Nonlinear Control
Issue number5
Publication statusPublished - 2019 Mar 25


  • disturbance rejection
  • equivalent-input-disturbance (EID)
  • generalized extended-state observer (GESO)
  • modified repetitive control (MRC)
  • nonlinearity
  • two-dimensional (2D) system

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Chemical Engineering(all)
  • Biomedical Engineering
  • Aerospace Engineering
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering
  • Electrical and Electronic Engineering


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