  This paper considers the distributed H-infinity leader-following tracking
problem for a class of discrete time multi-agent systems with a
high-dimensional dynamic leader. It is assumed that output information about
the leader is only available to designated followers, and the dynamics of the
followers are subject to perturbations. To achieve distributed H-infinity
leader-following tracking, a new class of control protocols is proposed which
is based on the feedback from the nearest neighbors as well as a distributed
state estimator. Under the assumptions that dynamics of the leader are
detectable and the communication topology contains a directed spanning tree,
sufficient conditions are obtained that enable all followers to track the
leader while achieving a desired H-infinity leader-following tracking
performance. Numerical simulations illustrate the effectiveness of the
theoretical analysis.
