Reduced-order disturbance observer design for discrete-time linear stochastic systems

Jinya Su, Baibing Li*, Wen Hua Chen, Jun Yang

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


Conventional disturbance observers for discrete-time linear stochastic systems assume that the system states are fully estimable and the disturbance estimate is dependent on the estimated system states, hereafter termed full-order disturbance observers (FODOs). This paper investigates the design of reduced-order disturbance observers (RODOs) when the system state variables are not fully estimable. An existence condition of RODOs is established, which is shown to be more easily satisfied than that of conventional FODOs and consequently it has substantially extended the scope of applications of disturbance observer theory. Then a set of recursive formulae for the RODO is developed for online applications. Finally, it is further shown that the conventional FODOs are a special case of the proposed RODO in the sense that the former reduces to the RODO when the states become fully estimable in the presence of disturbances. Examples are given to demonstrate the effectiveness and advantages of the proposed approach.

Original languageEnglish
Pages (from-to)657-664
Number of pages8
JournalTransactions of the Institute of Measurement and Control
Issue number6
Publication statusPublished - 1 Jun 2016

Bibliographical note

Publisher Copyright:
© 2016 SAGE Publications.


  • Disturbance observer
  • existence
  • Kalman filter
  • reduced-order
  • unknown input


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