Stabilization for Multirate Sampled-data Control Systems in case of Open-loop Unstable Plant

This paper proposes a stabilizing controller for multirate sampled-data systems which have a periodic output The proposed controller has IMC structure, and can be decomposed into a ye-stabilizing controller, an output estimator, a filtered disturbance estimator and the inverse of the fast ye-stabilized plant model. We assume that the plant is open-loop unstable and the disturbance consists of a sum of finite number of sinusoids with different frequencies. A sufficient condition for maintaining observability in the multirate sampled-data system is derived and a design strategy for filtered disturbance rejection is proposed. In addition, we propose a design method (or the plant output estimator. The simulation results show that the proposed stabilizing controllers can stabilize the plant