  This work addresses the problem of motion planning for a group of
nonholonomic robots under Visible Light Communication (VLC) connectivity
requirements. In particular, we consider an inspection task performed by a
Robot Chain Control System (RCCS), where a leader must visit relevant regions
of an environment while the remaining robots operate as relays, maintaining the
connectivity between the leader and a base station. We leverage Mixed-Integer
Linear Programming (MILP) to design a trajectory planner that can coordinate
the RCCS, minimizing time and control effort while also handling the issues of
directed Line-Of-Sight (LOS), connectivity over directed networks, and the
nonlinearity of the robots' dynamics. The efficacy of the proposal is
demonstrated with realistic simulations in the Gazebo environment using the
Turtlebot3 robot platform.
