  Many new methodologies for the control of large-scale multi-agent systems are
based on macroscopic representations of the emerging system dynamics, in the
form of continuum approximations of large ensembles. These techniques, that are
developed in the limit case of an infinite number of agents, are usually
validated only through numerical simulations. In this paper, we introduce a
mixed reality set-up for testing swarm robotics techniques, focusing on the
macroscopic collective motion of robotic swarms. This hybrid apparatus combines
both real differential drive robots and virtual agents to create a
heterogeneous swarm of tunable size. We also extend continuification-based
control methods for swarms to higher dimensions, and assess experimentally
their validity in the new platform. Our study demonstrates the effectiveness of
the platform for conducting large-scale swarm robotics experiments, and it
contributes new theoretical insights into control algorithms exploiting
continuification approaches.
