MODEL CONVERSIONS OF UNCERTAIN LINEAR-SYSTEMS USING INTERVAL MULTIPOINT FADE APPROXIMATION

Many dynamic systems and industrial control processes can be represent ed by a multirate sampled-data uncertain system, which consists of a c ontinuous-time uncertain subsystem and a multirate discrete-time uncer tain subsystem The uncertainties in these systems arise from unmodeled dynamics, parameter variations, sensor noises, actuator constraints, etc. As is the common practice the sampled-data uncertain system needs to be converted to a purely continuous-time or discrete-time uncertai n model, so that the well-established analysis and design methods in t he continuous-time or discrete-time domain can be directly applied to the equivalent model This paper presents a new interval multipoint Fad e approximation method for converting a continuous-time (discrete-time ) uncertain linear system to an equivalent discrete-time (continuous-t ime) uncertain model. The system matrices characterizing the state-spa ce descriptions of the original uncertain systems are represented by i nterval matrices. Using the approximate uncertain models obtained base d on interval analysis and multipoint Fade approximation the dynamic s tates of the resulting models have been shown to be able to closely ma tch those of the original uncertain systems for a relatively longer sa mpling period. (C) 1997 by Elsevier Science Inc.