Practical stability of descriptor systems with time delays in terms of two measurements

This paper introduces the concepts of practical stability for descriptor systems with time delays in terms of two measurements. Some results of practical stability parallel to Lyapunov stability theorems are given. Based on Lyapunov functions and the comparison principle, a criterion, by which the problem of a descriptor system with time delay is reduced to that of a standard state-space system without time delays, is derived. Finally, the application of the results obtained is demonstrated through an analysis of a class of linear time-invariant descriptor systems with time delay.