Estimation of the stability margin of 2-D state-space discrete systems

Methods to estimate the stability margin of 2-D discrete systems described in the state-space are presented. These methods are based on the 2-D Lyapunov equation with constant coefficients and on a sufficient condition for 2-D stability presented by R.P. Roesser (1975). The stability margin is estimated as a function of the system matrix and the positive definite solution to the 2-D Lyapunov equation with constant coefficients. Both the Roesser and Fornasini-Marchesini state-space descriptions are studied.<>