Digital modeling and hybrid control of sampled-data uncertain system with input time delay using the law of mean

This paper utilizes an interval Fade approximate method together with inter val arithmetic operation to convert a continuous-time uncertain system with input time-delay to an equivalent discrete-time interval model and transfo rms the robust control law of a continuous-time uncertain system with input time delay into an equivalent one of a sampled-data uncertain system with input time delay. The developed discrete-time interval model tightly enclos es the exact discrete-time uncertain system with input time delay. Based on the law of mean and inclusion theory, a perturbed digital control law of i nput time-delay sampled-data uncertain system is newly presented, so that t he states of the digitally controlled sample-data uncertain system closely match those of the originally well-designed continuous-time uncertain syste m. (C) 1999 Elsevier Science Inc. All rights reserved.