Robust stability and performance analysis of the control systems with higher order disturbance observer: Frequency approach

Emre Sariyildiz, Kouhei Ohnishi

Research output: Chapter in Book/Report/Conference proceedingConference contribution

13 Citations (Scopus)

Abstract

The Disturbance Observer (DOB) is widely used in many robust control applications such as robotics and industrial automation due to its simplicity and efficiency. The DOB estimates and compensates the system disturbances by using an inner-feedback loop in the range of its bandwidth. It includes the inverse of the nominal system model and a low pass filter (LPF) which determines the bandwidth of the DOB. The dynamic characteristic and bandwidth of the LPF directly affect the robust stability and performance of the system. The dynamic characteristic of the LPF can be adjusted by using Higher Order Disturbance Observers (HODOB). The bandwidth of the DOB is demanded to be as high as possible to suppress the system disturbances in a wide frequency range. However, it is bounded by the noise and robustness of the system. The conventional robustness analysis method which is based on the Small Gain theorem and unstructured uncertainties, unnecessarily limits the bandwidth of the DOB due to conservatism. The conservatism can be decreased by using the structured uncertainty based robustness analysis methods. In this paper, the robust stability and performance of the system with DOB/HODOB is analyzed by using the conventional analysis method and Singular Structured Values (SSV) that is based on the structured uncertainties. The pros and cons of these methods are shown. A general second order system model is analyzed and simulation results are given to show the validity of the proposed methods.

Original languageEnglish
Title of host publicationProceedings - 5th International Conference on Human System Interactions, HSI 2012
Pages67-74
Number of pages8
DOIs
Publication statusPublished - 2012 Dec 1
Event5th International Conference on Human System Interactions, HSI 2012 - Perth, WA, Australia
Duration: 2012 Jun 62012 Jun 8

Publication series

NameInternational Conference on Human System Interaction, HSI
ISSN (Print)2158-2246
ISSN (Electronic)2158-2254

Other

Other5th International Conference on Human System Interactions, HSI 2012
CountryAustralia
CityPerth, WA
Period12/6/612/6/8

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Keywords

  • Conservatism
  • Disturbance observer
  • Higher Order Disturbance Observer
  • Robust Control
  • Structred Singular Values

ASJC Scopus subject areas

  • Human-Computer Interaction
  • Software

Cite this

Sariyildiz, E., & Ohnishi, K. (2012). Robust stability and performance analysis of the control systems with higher order disturbance observer: Frequency approach. In Proceedings - 5th International Conference on Human System Interactions, HSI 2012 (pp. 67-74). [6473765] (International Conference on Human System Interaction, HSI). https://doi.org/10.1109/HSI.2012.20