  This paper investigates a distributed formation tracking control law for
large-scale networks of mechanical systems. In particular, the formation
network is represented by a directed communication graph with leaders and
followers, where each agent is described as a port-Hamiltonian system with a
constant mass matrix. Moreover, we adopt a distributed parameter approach to
prove the scalable asymptotic stability of the network formation, i.e., the
scalability with respect to the network size and the specific formation
preservation. A simulation case illustrates the effectiveness of the proposed
control approach.
