Model-based estimation of contact forces in rotating machines

Model-based fault detection in rotating machines has been the focus of several scientific and industrial efforts during the last decade (1,3,4). The main task of fault detection in the area of rotating machines is to conclude the existence of a shaft crack or the existence of a contact between rotating and fixed parts. In both cases the disturbance can be interpreted as an external force acting on the system. In practice the measurement of contact forces is difficult. The forces can only be obtained via the resulting vibration effects (displacement, strain). In this contribution, model-based observer techniques are used to estimate contact forces between rotor and housing.