  Identifying the most influential driver nodes to guarantee the fastest
synchronization speed is a key topic in pinning control of multi-agent systems.
This paper develops a methodology to find the most influential pinning nodes
under time-varying topologies. First, we provide the pinning control
synchronization conditions of multi-agent systems. Second, a method is proposed
to identify the best driver nodes that can guarantee the fastest
synchronization speed under periodically switched systems. We show that the
determination of the best driver nodes is independent of the system matrix
under certain conditions. Finally, we develop a method to estimate the
switching frequency threshold that can make the selected best driver nodes
remain the same as the average system. Numerical simulations reveal the
feasibility of these methods.
