LTR Design of Discrete-Time Proportional-Integra1 Observers - Automatic Control, IEEE Transactions on

This paper applies the proportional-integral (PI) observer in connection with loop-transfer recovery (LTR) design for discrete-time systems. Both the prediction and the filtering versions of the PI observer are considered. We show that a PI observer makes it possible to obtain time recovery, i.e., exact recovery for t + 00. under mild conditions. Two systematic LTR design methods, one based on an extension of the linear quadratic Gaussian loop-transfer recovery (LQGILTR) and the other based on linear matrix inequality (LMI), are derived for the discretetime PI observer case. Explicit expressions for the recovery error when exact recovery is not achievable for all frequencies are also given.