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Unknown input observers designed by eigenstructure assignment. (English) Zbl 1060.93022
Linear, continuous-time, finite-dimensional control systems with constant coefficients are considered. Using algebraic methods and certain matrix equalities, sufficient conditions for the existence of the full-order unknown input observers are formulated and proved. Next, robustness and eigenvalue sensitivity of the observers are discussed in detail. A simple method for the design of the full-order unknown input observer is presented and a numerical illustrative example is given. Moreover, many remarks and comments on the observer design problem for linear control systems are presented. Relationships to results existing in the literature are also given. Finally, it should be pointed out that similar problems have been considered in the papers: [N. Kobayashi and T. Nakamizo, “An observer design for linear systems with unknown inputs”, Int. J. Control 35, 605–619 (1982; Zbl 0487.93014) and F. Yang and R. W. Wilde, “Observers for linear systems with unknown inputs”, IEEE Trans. Autom. Control 33, No. 7, 677–681 (1988; Zbl 0646.93013)].

93B07 Observability
93B60 Eigenvalue problems
93B51 Design techniques (robust design, computer-aided design, etc.)
93B35 Sensitivity (robustness)
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