  Output feedback control design for linear time-invariant systems in the
presence of sporadic measurements and exogenous perturbations is addressed. To
cope with the sporadic availability of measurements of the output, a hybrid
dynamic output feedback controller equipped with a holding device whose state
is reset when a new measurement is available is designed. The closed-loop
system, resulting from the interconnection of the controller and the plant, is
augmented with a timer variable triggering the arrival of new measurements and
its properties are analyzed using hybrid system tools. Building upon Lyapunov
theory for hybrid systems, sufficient conditions for internal and L2
input-to-output stability are proposed. An LMI-based design methodology for the
co-design of the gains of the controller and the parameters of the holding
device is presented. The effectiveness of the proposed LMI-based design
approach is showcased in a numerical example.
