Sliding-mode observers for systems with unknown inputs: a high-gain approach. (English) Zbl 1205.93028

Kalsi, Karanjit; Lian, Jianming; Hui, Stefen; Żak, Stanislaw H.

Automatica 46, No. 2, 347-353 (2010).

Summary: Sliding-mode observers can be constructed for systems with unknown inputs if the so-called observer matching condition is satisfied. However, most systems do not satisfy this condition. To construct sliding-mode observers for systems that do not satisfy the observer matching condition, auxiliary outputs are generated using high-gain approximate differentiators and then employed in the design of sliding-mode observers. The state estimation error of the proposed high-gain approximate differentiator based sliding-mode observer is shown to be uniformly ultimately bounded with respect to a ball whose radius is a function of design parameters. Finally, the unknown input reconstruction using the proposed observer is analyzed and then illustrated with a numerical example.

MSC:

93B12	Variable structure systems
93B07	Observability

Keywords:

sliding-mode observer; high-gain approximate differentiator; unknown input reconstruction

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