  This paper studies the structural controllability of a class of uncertain
switched linear systems, where the parameters of subsystems state matrices are
either unknown or zero. The structural controllability is a generalization of
the traditional controllability concept for dynamical systems, and purely based
on the interconnection relation between the state variables and inputs through
non-zero elements in the state matrices. In order to illustrate such a
relationship, two kinds of graphic representations of switched linear systems
are proposed, based on which graph theory based necessary and sufficient
characterizations of the structural controllability for switched linear systems
are presented. Finally, the paper concludes with discussions on the results and
future work.
