Discretization of cascaded continuous-time controllers for state and inputdelayed systems

This paper presents a new interpolation method that utilizes a Newton backw ard interpolation formula for the discretization of a continuous-time syste m with state and input delays. Also, a new output feedback state-matching d igital redesign method, which utilizes the Newton extrapolation formula and the Chebyshev quadrature formula, enables the discretization of a cascaded continuous-time controller or filter for the continuous-time systems with delayed input and states, without employing a discrete-time observer. The p roposed method provides an alternative methodology for indirect digital des ign of a continuous-time unity-output feedback delayed system and enables u s to implement accurately and effectively an existing or pre-designed casca ded analogue controller or filter via a digital controller.