Adaptive control of systems subject to deterministic time-varying disturbances via an additional measurement

An additional measurement is introduced into an adaptive control scheme for reducing the undesirable effects caused by the unknown deterministic time-varying disturbances. The additional measurement is utilized in one-step-ahead controller to result in a zero tracking error. It also results in an estimation algorithm, which achieves unbiased parameter estimates without increasing the number of the parameters to be estimated. Global convergence and stability for the closed loop adaptive control systems are established under the ideal condition. Simulation results show that the adaptive control system is stable when the disturbance is actually not a polynomial