Robust stability condition for continuous-time systems

New linear matrix inequalities (LMIs) are presented for robust stability of uncertain continuous-time systems. The LMIs do not involve any product of the Lyapunov matrix and the system dynamic matrix thus enables the checking of stability using parameter-dependent Lyapunov matrices. The condition is less conservative than previously presented conditions. The reduction in conservativeness is achieved by the introduction of an instrumental variable. A simple numerical example is given to illustrate the results.