On strong structural controllability of linear systems

Both a novel graphic-theoretic condition and novel algebraic conditions are presented for the strong structural controllability of linear MIMO (multiple-input multiple output) systems. These conditions can be checked by a given algorithm with a complexity O(n/sup 3/). Whereas the graph-theoretic approach is very useful for low-order systems allowing a visual inspection, the algebraic approach is especially suited for computer-aided analysis of large-scale systems. A new efficient algorithm is also given.<<ETX>>