Using preaction to eliminate tracking error in feedback control of nonminimum phase systems

The approximately zero transient output tracking problem is considered in this article for single-input/single-output nonminimum phase linear dynamical systems. Based on the previewed information of the reference input, the proposed controller reduces the transient error arbitrarily close to zero. The controller presented here contains “supervising unit” that can read and change the states of the internal model and compensator as necessary. The supervising unit combined with a robust regulator based on internal model principle provide near zero transient tracking error as well as robustness in asymptotic tracking