THE LINEAR OUTPUT RESIDUAL METHOD WITH COMPUTATIONALLY ADAPTIVE EXCITATION IN THE FREQUENCY-DOMAIN .1. THEORY

In this payer a linear parameter estimation procedure based on input a nd output measurements in the frequency domain is described. The metho d can also be used if the output measurements are not available for al l the components of the mathematical model. The following problems of the method are discussed: ill-posedness (input residual method), non-l inearity and the small region of attraction for the global minimum (ou tput residual method) and unrealizable excitations (selective sensitiv ity). The method is based on an approximation of frequency response ma trices by existing input and output measurements. These approximations are used to approximate the system responses for adaptive calculated excitations. The aim functional derived from these considerations cons ists of the L-2-difference of the constant mathematical model response and the approximated system response for the computationally adaptive excitations. The adaptivity of the calculated excitation is chosen su ch that a possible bias is reduced. In the case of complete output mea surements or of the sufficient excitation of the essential modes in th e frequency interval under consideration, the method performs an unbia sed estimate of the parameters sought. (C) 1997 Academic Press Limited .