Avoiding Collisions in Flocks

Among the many models for flocking systems of interacting particles, the one introduced by Cucker and Smale has attracted attention due to the fact that a convergence to flocking (i.e., to a common velocity) could be established depending on conditions on the initial state of the system. In this note we extend this model by adding to it a repelling force between particles. We show that, for this modified model, convergence to flocking is established along the same lines while, in addition, avoidance of collisions (i.e., the respect of a minimal distance between particles) is ensured.