Identification for Robust Control of Flexible Structures

Abstract

An accurate multivariable transfer function model of an experimental structure is required for research involving robust control of flexible structures. Initially, a multi-input/multi-output model of the structure is generated using the finite element method. This model was insufficient due to its variation from the experimental data. Therefore, Chebyshev polynomials are employed to fit the data with a single-input/multi-output transfer function models. Combining these lead to a multivariable model with more modes than the original finite element model. To find a physically motivated model, as ad hoc model reduction technique which uses a priori knowledge of the structure is developed. The ad hoc approach is compared with balanced realisation model reduction to determine its benefits. Plots of select transfer function models and experimental data are included.