Speed dependent dynamic parameters estimation of a rotor–bearing–coupling system

Abstract

In the modelling and analysis of turbine generator systems, bearing and coupling dynamic parameters are considered as the major unknowns. In the past, practitioners of rotor dynamics have modelled coupling as having speed independent stiffness and damping parameters that lead to modelling error, due to the fact that the amount of misalignment depends upon different modes of excitation. In this article, an identification algorithm has been developed for simultaneous estimation of the speed dependent bearing and coupling dynamic parameters along with residual unbalances. Lagrange’s equation is used to derive the equations of motion of the system in generalized coordinates and least squares technique is used to develop identification algorithm. The novelty of the present identification algorithm is the estimation of speed dependent coupling dynamic parameters along with speed dependent bearing dynamic parameters. Numerical experiments have been performed for a simple rotor train model to illustrate the developed algorithm. To check the robustness of the identification algorithm, measurement noise has been added in numerically simulated response. Well agreement in the estimated parameters is observed for a different level of measurement noise.