Intersample output estimation with multirate sampling

A controller when implemented with a multirate sampling scheme, i.e. plant output sampled at a slower rate than the control input, contains less information about the system dynamics than a traditional implementation. This makes the overall closed loop system loosely controlled with higher overshoots and large settling times. This paper examines three different strategies of tightening the control in the multirate sampling scheme. Two schemes are numerical techniques, where the intersample behavior of the plant is predicted using the available sampled plant output information. The third technique uses a linearized plant model in conjunction with a discrete time state estimator. These algorithms are implemented on a second order system scaled from an actual electro-mechanical system