Tracking controller design for a class of nonminimum-phase systems via the method of system center

A method of approximate output tracking for a class of causal nonminimum-phase multiple-input-multiple-output (MIMO) systems with nonlinear time-varying uncertainties and unmeasurable disturbances is considered. The nonminimum-phase output-tracking problem is transformed into a state-tracking problem. The technique presented employs linear algebraic methods and the internal model principle. A sliding mode control approach is used in the example to illustrate a complete constructive algorithm.