Output-error identification methods for partially known systems

Output-error methods are applied to the problem of identifying partially known linear time-invariant finite-dimensional systems. The systems considered have a limited number of unknown parameters, which are assumed to enter the numerator and denominator of the transfer function multilinearly. This is representative of mechanical and electrical systems with unknown inertias, frictional coefficients, inductances or resistances. Two output-error schemes are developed and shown to be uniformly asymptotically convergent under certain conditions.