DISCRETIZATION OF CASCADED CONTINUOUS-TIME CONTROLLERS AND UNCERTAIN SYSTEMS

This paper presents a new method for the digital modeling of a continu ous-time uncertain system and a new method for the digital redesign of a sampled-data uncertain system. The system matrices characterizing t he state-space representation of the original uncertain system are ass umed to be interval matrices. The Chebyshev quadrature formula togethe r with the interval arithmetic are used for the digital interval model ing, and a dual concept of digital interval modeling is utilized to di scretize a predesigned cascaded analog controller for robust digital c ontrol of a continuous-time uncertain system. Using the newly develope d digital interval models and digitally redesigned controllers, the re sulting dynamic states of the digitally controlled sampled-data uncert ain systems are able to closely match those of the originally analogou sly controlled continuous-time uncertain systems for a relatively long er sampling period.