A stability robustness test via quadratic Lyapunov forms

The stability robustness problem for a class of nominally linear systems subject to time-varying parameter uncertainty is dealt with. The allowable range of parameter variation is assumed to be a hyperrectangle in parameter space. The proposed robustness test, which is based on a Lyapunov approach, requires a finite number of positivity tests of a quadratic form in correspondence to some salient points in parameter space