Design of l1-suboptimal multirate controllers

A computer aided design method for linear multirate digital control systems is presented. The design procedure is based on the well known lifting technique and the l₁-system norm. It is shown how the standard l₁-control system design problem has to be augmented with additional constraints in order to maintain the causality of the controller and to avoid undesired ripples in the system output. Moreover it turns out, that multirate digital controllers may be a remedy against the problem of high controller order in l₁-control.