Adaptive servo controller for systems with unknown degrees and uncertain relative degrees

Presents a novel approach to the design of adaptive servo controllers for systems with unknown degrees and uncertain relative degrees. Contrary to the previous researches where the degrees and relative degrees of controlled systems are assumed to be known, the degrees in the present paper are completely unknown, and the relative degrees are partly unknown; that is, the relative degrees are known to be r, r+1, or r+2 with known r. It is shown that the proposed servo controllers stabilize systems with such uncertainties, and estimate unknown internal models of disturbances and reference signals. The asymptotic stability of error systems is proved without any assumption on sufficient excitation of signals