Microsoft Word - WCECS2012_Augmented_Observer

Disturbances and model uncertainties often have large impact on model based fault detection and isolation (FDI) processes and result in false alarm or reduced fault detection rate. In rotor systems exited by unbalances, the predominant disturbances (e.g. unbalance forces) and model uncertainties caused by gyroscopic effect appear in a sinusoidal form with rotor rotary frequency. If the influences of disturbances and model uncertainties are to be represented using unknown inputs, the signals of unknown inputs should also be sinusoidal. Augmented observers that account for sinusoidal unknown inputs are designed in this paper to take advantage of this characteristic of rotor systems. Different configurations of the augmented observer are investigated to estimate the distribution matrix of unknown inputs and for the residual generation under the consideration of unknown inputs. In case that the faults (e.g. rotor disc break) acting on the rotor are also in sinusoidal form the augmented observer can be used for fault isolation and identification.