Extending the Root-Locus Method to Fractional-Order Systems

Autor: Farshad Merrikh-Bayat, Mahdi Afshar
Jazyk: angličtina
Rok vydání: 2008
Předmět:
Zdroj: Journal of Applied Mathematics, Vol 2008 (2008)
Druh dokumentu: article
ISSN: 1110-757X
1687-0042
DOI: 10.1155/2008/528934
Popis: The well-known root-locus method is developed for special subset of linear time-invariant systems known as fractional-order systems. Transfer functions of these systems are rational functions with polynomials of rational powers of the Laplace variable s. Such systems are defined on a Riemann surface because of their multivalued nature. A set of rules for plotting the root loci on the first Riemann sheet is presented. The important features of the classical root-locus method such as asymptotes, roots condition on the real axis, and breakaway points are extended to fractional case. It is also shown that the proposed method can assess the closed-loop stability of fractional-order systems in the presence of a varying gain in the loop. Three illustrative examples are presented to confirm the effectiveness of the proposed algorithm.
Databáze: Directory of Open Access Journals