On exponential stability conditions of descriptor systems with time-varying delay

We are interested in the exponential stability of the descriptor system,which is composed of the slow and fast subsystems with time-varying delay. in computing a kind of lyapunov functional,we employ a necessary number of slack matrices to render the balance and to yield the convexity condition for reducing the conservatism and dealing with the case of time-varying delay. therefore,we can get the decay rate of the slow variables. moreover,we characterize the effect of the fast subsystem on the derived decay rate and then prove the fast variables to decay exponentially through a perturbation approach. finally,we provide an example to demonstrate the effectiveness of the method. copyright © 2012 s. cong and z.-b. sheng.