Experiment design for improved frequency domain subspace system identification of continuous-time systems
Journal article, 2015

A widely used approach for identification of linear, time-invariant, MIMO (multi-input/multi output) systems from continuous-time frequency response data is to solve it in discrete-time domain using subspace based identification algorithm incorporated with a bilinear transformation. However, the bilinear transformation maps the distribution of the frequency lines from continuous-time domain to discrete-time domain in a non-linear fashion which may make identification algorithm to be ill-conditioned. In this paper we propose a solution to get around this problem by designing a dedicated frequency sampling strategy. Promising results are obtained when the algorithm is applied to synthetic data from a 6DOF mass-spring model.

Subspace methods

Frequency sampling strategy

Frequency responses

System identification

Bias reduction


Majid Khorsand Vakilzadeh

Chalmers, Applied Mechanics, Dynamics

Vahid Yaghoubi Nasrabadi

Chalmers, Applied Mechanics, Dynamics

Tomas McKelvey

Chalmers, Signals and Systems, Signalbehandling och medicinsk teknik, Signal Processing

Thomas Abrahamsson

Chalmers, Applied Mechanics, Dynamics

Lennart Ljung

Linkvping University


2405-8963 (ISSN)

Vol. 48 886-891

Subject Categories

Mechanical Engineering