Design of robust digital set-point tracking controllers for linear multivariable plants with time-delayed inputs

It is shown that, for a large class of linear multivariable plants with multiple time-delayed inputs, robust digital set-point tracking controllers can be readily designed. The general design methodolgy is based upon the asymptotic analysis of the closed-loop characteristic roots of digitally controlled plants for large sampling periods, and is illustrated by designing a robust digital set-point tracking controller for a boiler furnace with four inputs and four outputs.