Selection of Outputs for Gas-Turbine Engines by Parameter Signatures

Abstract

A method of measurement selection is introduced that relies on parameter signatures to assess the identifiability of dynamic model parameters by different outputs. A parameter signature is a region in the time-scale plane wherein the sensitivity of the output with respect to one model parameter is much larger than the rest of output sensitivities. Since the existence of a parameter signature is synonymous with the uniqueness of the corresponding output sensitivity, parameter signatures are directly linked to parameter identifiability by outputs and, hence, can be used for output/measurement selection. The purpose of this paper is to introduce a strategy for measurement selection by parameter signatures and to demonstrate its applicability to the transient decks of turbo-jet engines. The validity of the selected outputs in providing observability to the engine model parameters is independently verified by successful estimation of parameters by nonlinear least-squares.