title: Identifiability of fractional order systems using input output frequency contents.
abstract: In this paper, issues related to the identifiability of a fractional order system having its input and output frequency contents are discussed. The effects of the commensurate order alpha in the identifiability of the model structure and model parameters are analytically studied. It is shown that both identifiabilities (model structure and model parameters) are reduced remarkably for smaller values of alpha. This phenomenon is observed even though the input signals are rich enough and system belongs to the model set. Our understanding is that the problem arises since differences among different members of the model set fall beyond the practically recognizable precision range. The issue is more problematic when alpha is smaller and measurements are noisy.
authors.affiliation: Electrical Engineering Department, Islamic Azad University, Science and Research Branch, Tehran, Iran. pay_naz@yahoo.com
authors.forename: Peyman
authors.initials: P
authors.lastname: Nazarian
authors.forename: Mohammad
authors.initials: M
authors.lastname: Haeri
authors.forename: Mohammad Saleh
authors.initials: MS
authors.lastname: Tavazoei
mesh_terms: D000465:Algorithms; D003365:Costs and Cost Analysis; D004738:Engineering; D015233:Models, Statistical; D017711:Nonlinear Dynamics