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Stability analysis of large scale systems whose subsystems may be unstable. (English) Zbl 0538.93048
A method is proposed for studying the stability of nonlinear, stationary, interconnected systems. In particular the case is considered of two interconnected systems in the form $$\dot x_ i=f_ i(x_ i)+g_ i(x_ i,x_ 2),\quad i=1,2.$$ Lyapunov functions are constructed for the individual systems (i.e. with $$g_ i=0)$$, together with a function $$v_{12}(x_ 1,x_ 2)$$ representing ”energy coupling” between the subsystems. A weighted sum of these functions is taken as a candidate for a Lyapunov function for the full system, and a sufficient condition is obtained for system stability. A method for constructing $$v_{12}$$ is suggested and the technique is illustrated with two examples.
Reviewer: D.A.Wilson

##### MSC:
 93D05 Lyapunov and other classical stabilities (Lagrange, Poisson, $$L^p, l^p$$, etc.) in control theory 93A15 Large-scale systems 93C10 Nonlinear systems in control theory 93C15 Control/observation systems governed by ordinary differential equations 34D20 Stability of solutions to ordinary differential equations