Adaptive optimal robust tracking of discrete-time minimum-phase plant under biased disturbance

This paper addresses a problem of adaptive optimal robust tracking of discrete-time minimum-phase SISO plant under biased total disturbance in the form of output uncertainty and bounded external disturbance. Coefficients of nominal model, a gain of output uncertainty, an upper bound of external disturbance, and bias are unknown to controller designer. The control criterion in the form of the worst-case steady-state tracking error over permitted uncertainties and disturbances is used as an identification criterion. Solution of the problem is based on polyhedral estimation of data-consistent parameters and computation of optimal current estimates.