Abstract
This paper deals with the design of optimal control for unstable time-delayed
systems. Delays can be considered either at the output (measurement delays), the input
(actuator delays) or both including transmission delays. The system could be unstable. The
cost index weights the system state and the control input. Fully state accessibility is
assumed, but the option of output dynamic feedback through an observer can be
considered. This result can be split into a predictor followed by a state estimator
