Analysis the robustness of control systems based on disturbance observer

Emre Sariyildiz, Kouhei Ohnishi

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)


Disturbance observer (DOB) estimates the system disturbances by using the inverse of the nominal plant model and a low pass filter (LPF). Although the LPF provides the properness in the inner-loop, it is the main design constraint of the control systems based on DOB. The bandwidth of the LPF is designed as high as possible so that the DOB can estimate the disturbances in a wider frequency range. However, its bandwidth is limited by noise and robustness of the system. The robustness limitation is directly related with the robustness analysis methods, and they significantly affect the performance of the DOB based control systems. In this paper, three different robustness analysis methods are implemented into the DOB based control systems, and the relation between the robustness of the system and bandwidth of DOB is clearly explained. The conservatism, which is the main drawback of the conventional analysis methods, on the bandwidth of DOB is removed by proposing a new real parametric uncertainty based analysis method. The proposed methods are compared in detail, and simulation results are given to show the validation.

Original languageEnglish
Pages (from-to)1733-1743
Number of pages11
JournalInternational Journal of Control
Issue number10
Publication statusPublished - 2013 Oct 1


  • disturbance observer
  • robust control
  • singular structured values
  • system uncertainties

ASJC Scopus subject areas

  • Control and Systems Engineering
  • Computer Science Applications


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