A sliding mode observer for infinitely unobservable descriptor systems

Jeremy Hor Teong Ooi, Chee Pin Tan, Surya Girinatha Nurzaman, Kok Yew Ng

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34 Citations (Scopus)


In existing work of sliding mode observers (SMOs) for descriptor systems, a necessary condition is that the system must be infinitely observable. This paper presents a scheme that circumvents that condition, by reformulating the system as a reduced-order system where certain structures in the system matrix are manipulated and certain states are treated as unknown inputs. Following that, an SMO is implemented on the reduced-order system where state and fault estimation can be achieved. Necessary and sufficient conditions of this scheme are also presented. Finally, a simulation example shows the effectiveness of the proposed scheme.

Original languageEnglish
Pages (from-to)3580-3587
Number of pages8
JournalIEEE Transactions on Automatic Control
Issue number7
Publication statusPublished - Jul 2017


  • Estimation
  • fault detection
  • linear systems
  • sliding mode observers (SMOs)

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