Robust stability of digital feedback control systems with floating point arithmetic

This paper deals with the problem of robust stability for a class of digital control systems of uncertain continuous-time plants with interval time-varying parameter uncertainties. We study the influence of the effects of quantization and finite wordlength in the floating point (FLP) implementation of the digital controller on robust stability. An approach is developed in which these effects can be analyzed in the framework of a deterministic model. Based on this approach we obtain sufficient conditions for robust stability of the corresponding idealized hybrid control system. The estimates for asymptotic response bounds in real hybrid control systems are also derived by means of Lyapunov functions method.