  Swarms of coupled mobile agents subject to inter-agent wireless communication
delays are known to exhibit multiple dynamic patterns in space that depend on
the strength of the interactions and the magnitude of the communication delays.
We experimentally demonstrate communication delay-induced bifurcations in the
spatio-temporal patterns of robot swarms using two distinct hardware platforms
in a mixed reality framework. Additionally, we make steps toward experimentally
validating theoretically predicted parameter regions where transitions between
swarm patterns occur. We show that multiple rotation patterns persist even when
collision-avoidance strategies are incorporated, and we show the existence of
multi-stable, co-existing rotational patterns not predicted by usual mean field
dynamics. Our experiments are the first significant steps towards validating
existing theory and the existence and robustness of the delay-induced patterns
in real robotic swarms.
