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Frequency-Domain Identification of Linear Time-Periodic Systems using LTI Techniques (2009)
| Content Provider | CiteSeerX |
|---|---|
| Author | Allen, Matthew S. |
| Description | A variety of systems can be faithfully modeled as linear with coefficients that vary periodically with time or Linear Time-Periodic (LTP). Examples include anisotropic rotor-bearing systems, wind turbines and nonlinear systems linearized about a periodic trajectory; all of these have been treated analytically in the literature. However, few methods exist for experimentally characterizing LTP systems. This paper presents a set of tools that can be used to experimentally characterize an LTP system, using a frequency domain approach and utilizing existing algorithms to perform parameter identification. One of the approaches is based on lifting the response to obtain an equivalent Linear Time-Invariant (LTI) form and the other based on Fourier series expansion. The development focuses on the pre-processing steps needed to apply LTI identification to the measurements, the post-processing needed to reconstruct the LTP model from the identification results and the interpretation of the measurements. This approach elucidates the similarities between LTP and LTI identification, allowing the experimentalist to transfer insight from time-invariant systems to the LTP identification problem. The approach determines the model order of the system, and post processing reveals the shapes of the time-periodic functions comprising the LTP model. Further post-processing is also presented that allows one to generate the full state transition matrix and the time-varying state matrix of the system from the parametric model if the measurement set is adequate. The experimental techniques are demonstrated on simulated measurements from a Jeffcott rotor mounted on an anisotropic, flexible shaft, supported by anisotropic bearings. 1. |
| File Format | |
| Language | English |
| Publisher Date | 2009-01-01 |
| Publisher Institution | Page 28 of 28 Prepublication Manuscript for MSSP Allen & Sracic |
| Access Restriction | Open |
| Subject Keyword | Lti Identification Pre-processing Step Time-varying State Matrix Linear Time-periodic System Anisotropic Bearing Anisotropic Rotor-bearing System Simulated Measurement Flexible Shaft Experimental Technique Nonlinear System Identification Result Periodic Trajectory Equivalent Linear Time-invariant Full State Transition Matrix Parametric Model Model Order Parameter Identification Ltp Model Frequency-domain Identification Fourier Series Expansion Time-periodic Function Jeffcott Rotor Wind Turbine Time-invariant System Measurement Set Lti Technique Ltp Identification Problem Ltp System Post Processing Frequency Domain Approach |
| Content Type | Text |
| Resource Type | Article |
