Robustness Analysis of Digital Feedback Control Systems with Time-varying Sampling Periods

In the present paper, we study robustness properties of a class of digital feedback control systems with time-varying sampling periods consisting of an interconnection of a continuous-time nonlinear plant (described by systems of rst-order ordinary diierential equations), a nonlinear digital controller (described by systems of rst-order ordinary diierence equations), and appropriate interface elements between the plant and controller (A/D and D/A converters). For such systems, we establish results for exponential stability of an equilibrium (in the Lyapunov sense) in the presence of vanishing perturbations and for the boundedness of solutions (i.e., Lagrange stability) under the innuence of non-vanishing perturbations. We apply these results in the study of quantization eeects.