  In this paper, we propose the safety barrier certificates for uncertain
multi-robot systems playing red light, green light game. According to the rule
of the game, the robots are allowed to move forward after a doll shouts `green
light' and must stop when it shouts `red light'. Following this rule, a
two-mode nominal controller is designed where one mode is for moving forward
and the other one is for slowing down and being motionless. Then, multiple
exponential control barrier functions(ECBFs) are developed to handle safety
constraints for limited playground, collision avoidance, and saturation of the
velocity. While designing the nominal controller and ECBFs, an estimated
braking time and robust inequality constraints are derived to deal with the
system uncertainty. Consequently, a controller guaranteeing safety barrier
certificates of each robot has been formulated by a quadratic programming with
the nominal controller and the robust inequality constraints. Finally, red
light, green light game is simulated to validate the proposed safety-critical
control system.
