Robust ℋ∞ filtering for nonuniformly sampled systems

We consider the design of a robust ℋ∞ filter for sampled-data systems whose measurements are sampled at uncertain and nonuniform sampling instants. A discrete-time, fixed-structure filter is considered. The resulting error system is time-varying, which makes the filter design difficult. A procedure is presented to design the filter so that the error system remains asymptotically stable for all possible variations of the sampling period with an ℋ∞ performance level. The effectiveness of the proposed method is demonstrated through numerical examples.