Frequency adaptive control of a stable plant under unknown bounded disturbances

An adaptation algorithm for the coefficients of a controller for an asympto tically stable plant under unknown bounded disturbance is proposed. The alg orithm makes use of a rather small harmonic test signal which allows for th e identification of the plant and the closed-loop system (with a modal cont roller) with the required accuracy. The results of identification of the ch aracteristic polynomial of the closed-loop system are compared with the coe fficients of a desired polynomial, and the adaptation process is terminated if they are close to each other. The conditions imposed on the disturbance are obtained which ensure the convergence of the adaptation process. These conditions can be verified experimentally.