Robust observer-based stabilizer of singularly perturbed systems: sampled-data control approach

It is argued that, when a singularly perturbed proper plant is preceded by a zero-order-hold, the direct and the induced direct (resulting from neglecting unmodeled high-frequency dynamics) transmission terms of the reduced-order model should be treated as two distinct terms; the latter contains a delay element and the former does not. It is shown that the observer-based sampled-data controller for the reduced-order model can stabilize the original plant for sufficiently small values of the singular perturbation parameter