An Adaptive Controller for Systems with Unmeasurable Disturbance

By using internal model principle, this paper proposes a simple adaptive controller for time invariant multivariable linear system in discrete time with unmeasurable external disturbances. The controller incorporates an internal mode of external disturbances and reference signals as well as exogenous stabilizing signals, and makes the tracking error asymptotically tend to zero and the whole system globally asymptotically stable under suitable assumptions.