  In this paper we study the emergence of coherence in collective motion
described by a system of interacting motiles endowed with an inner, adaptative,
steering mechanism. By means of a nonlinear parametric coupling, the system
elements are able to swing along the route to chaos. Thereby, each motile can
display different types of behavior, i.e. from ordered to fully erratic motion,
accordingly with its surrounding conditions. The appearance of patterns of
collective motion is shown to be related to the emergence of interparticle
synchronization and the degree of coherence of motion is quantified by means of
a graph representation. The effects related to the density of particles and to
interparticle distances are explored. It is shown that the higher degrees of
coherence and group cohesion are attained when the system elements display a
combination of ordered and chaotic behaviors, which emerges from a collective
self-organization process.
