Analysis of nonlinear time-delay systems using the sum of squares decomposition

The use of the sum of squares decomposition and semidefinite programming have provided an efficient methodology for analysis of nonlinear systems described by ODEs by algorithmically constructing Lyapunov functions. Based on the same methodology we present an algorithmic procedure for constructing Lyapunov-Krasovskii functional for nonlinear time delay systems described by functional differential equations (FDEs) both for delay-dependent and delay-independent stability analysis. Robust stability analysis of these systems under parametric uncertainty can be treated in a unified way. We illustrate the results with an example from population dynamics.