Conditioning of regression matrices for simultaneous estimation of the residual unbalance and bearing dynamic parameters

A general identification algorithm has been presented for multi-degree-of-freedom rotor-bearing systems. A specific identification algorithm for simultaneous estimation of the residual unbalance and bearing dynamic parameters in rotor-bearing systems has been developed. The identification algorithm is found to be highly ill-conditioned for the conventional measurement techniques. The measurement of responses, while rotating the rotor alternatively in clockwise or counter clockwise direction leads to a well-conditioned identification algorithm. Numerical examples have been used to illustrate the developed algorithms. The algorithm is tested against the measurement noise and found to be robust.