Abstract:

We consider a class of problems where robots
gather observations of each other to assess the legitimacy
of their peers. Previous works propose accurate detection of
malicious robots when robots are able to extract observations of
each other for a long enough time. However, they often consider
static networks where the set of neighbors a robot observes
remains the same. Mobile robots experience a dynamic set of
neighbors as they move, making the acquisition of adequate
observations more difficult. We design a stochastic policy that
enables the robots to periodically gather observations of every
other robot, while simultaneously satisfying a desired robot
distribution over an environment modeled by sites. We show
that with this policy, any pre-existing or new malicious robot in
the network will be detected in a finite amount of time, which
we minimize and also characterize. We derive bounds on the
time needed to obtain the desired number of observations for a
given topological map and validate these bounds in simulation.
We also show and verify in a hardware experiment that the
team is able to successfully detect malicious robots, and thus
estimate the true distribution of cooperative robots per site, in
order to converge to the desired robot distribution over sites.