Delayed model following for nonminimum phase plants

It is known that exact model following cannot be executed for both continuous time and discrete time nonminimum phase plants. For discrete time systems, it is shown that the waveform of y(k), the output of the closed loop system, can be made as desired as that of y_m(k), the reference model output, at the cost of the delay in the output y(k). For continuous time systems, it is shown that the magnitude of the reverse action as well as the waveform between the output of the closed loop system and the reference model output can be made as small as desired at the cost of the delay in the output y(t). Both the principle and the design method, however, are quite different between two systems