Comments on: “When retarded nonlinear time-delay systems admit an input-output representation of neutral type”. (English) Zbl 1507.93106
Summary: It is shown that the claim \(( i )\) of Theorem 13 in the commented article is actually not true, i.e., there does not always exist a \(( s + 1 )\) th order retarded type input-output equation for a nonlinear time-delay system with observability index \(s\). For some special cases the existence of a retarded type input-output equation is described.
MSC:
93C15 | Control/observation systems governed by ordinary differential equations |
93C10 | Nonlinear systems in control theory |
34K40 | Neutral functional-differential equations |
93B25 | Algebraic methods |
Keywords:
nonlinear time-delay systems; neutral systems; retarded systems; input-output representation; algebraic approachReferences:
[1] | Califano, C.; Moog, C. H., Observability of nonlinear time-delay systems and its application to their state realization, IEEE Control Systems Letters, 4, 4, 803-808 (2020) |
[2] | Halás, M.; Anguelova, M., When retarded nonlinear time-delay systems admit an input-output representation of neutral type, Automatica, 49, 2, 561-567 (2013) · Zbl 1259.93066 |
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