On the stability of symmetric nonlinear output-coupled multivariable systems

A Lyapunov function together with a modified Meyer-Kalman-Yakubovitch lemma are used to develop absolute stability conditions for autonomous symmetric nonlinear output-coupled multivariable systems. The nonlinear characteristics are restricted in both sector and slope. As an example, a coupled-core nuclear reactor with typical parameters is considered to illustrate the concepts developed in this correspondence.