  COVID-19 pandemic has become a global challenge faced by people all over the
world. Social distancing has been proved to be an effective practice to reduce
the spread of COVID-19. Against this backdrop, we propose that the surveillance
robots can not only monitor but also promote social distancing. Robots can be
flexibly deployed and they can take precautionary actions to remind people of
practicing social distancing. In this paper, we introduce a fully autonomous
surveillance robot based on a quadruped platform that can promote social
distancing in complex urban environments. Specifically, to achieve autonomy, we
mount multiple cameras and a 3D LiDAR on the legged robot. The robot then uses
an onboard real-time social distancing detection system to track nearby
pedestrian groups. Next, the robot uses a crowd-aware navigation algorithm to
move freely in highly dynamic scenarios. The robot finally uses a crowd-aware
routing algorithm to effectively promote social distancing by using
human-friendly verbal cues to send suggestions to over-crowded pedestrians. We
demonstrate and validate that our robot can be operated autonomously by
conducting several experiments in various urban scenarios.
