A nonlinear disturbance observer scheme for discrete time control systems

EFE M. Ö., KASNAKOĞLU C.

TURKISH JOURNAL OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCES, vol.29, no.2, pp.1044-1060, 2021 (SCI-Expanded) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 29 Issue: 2
  • Publication Date: 2021
  • Doi Number: 10.3906/elk-2005-206
  • Journal Name: TURKISH JOURNAL OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCES
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Applied Science & Technology Source, Compendex, Computer & Applied Sciences, INSPEC, TR DİZİN (ULAKBİM)
  • Page Numbers: pp.1044-1060
  • Keywords: Discrete time disturbance observer, robust control, nonlinear Q-filter, S-filter, REJECTION
  • Hacettepe University Affiliated: Yes

Abstract

This paper presents a modification to the original disturbance observer based control (DOBC) scheme by redefining the lowpass filter using a nonlinear element. The proposed technique improves the disturbance prediction performance for both small and large magnitude disturbance signals. The contribution of the current work is to unfold the stability and performance conditions under the proposed modification. A comparative set of simulation studies are discussed and it is seen that the proposed modification results in smaller disturbance prediction error energy and smaller tracking error energy when the plant model is discrete time and uncertain.