Digital controller improvement by multirate control

Digital control of continuous time processes is usually designed on the basis of a constant sampling rate. The use of multirate strategies can improve the time or frequency specifications of the process output, modifying the overshoot, the settling time, hidden oscillations, or the phase and magnitude margins. A new methodology based in classical techniques is presented in order to provide a closed loop model suitable to compare different structures and their associated performances. Finally, the control of a DC motor confirms the results obtained