Improvement of deadbeat servomechanism using multirate input control

Proposes a state-space approach to deadbeat servomechanism design using multirate input control. The focus is on the advantage of multirate control over conventional single-rate control. Multirate controllers can achieve required settling time with less frequent sampling of measurement. The multirate input mechanism can yield shorter settling time than single-rate control using the same frequency of sampling. In general, multirate control exhibits intersample ripple. Nevertheless, the paper demonstrates that the negative effect of multirate input on the steady-state response can be removed completely to accomplish ripple-free deadbeat, keeping the settling time short using the multirate mechanism at the same time. In addition, the paper presents a design method for multirate ripple-free deadbeat control which guarantees robustness against continuous-time disturbance and model uncertainty.