In this research, we analyze a formation control of a multi-robot system while considering the limitation of communication range for each robots. With limitation in communication range, it is important to control the communication network topology of a multi-robot system in order to keep the network's connectivity. We formulate the multi-robot system as a hybrid dynamical system, with the communication constraints by inequality. Then we study the algorithm to solve a mixed integer programming problem that is equivalent to the optimal formation control probrem of the system. Computer simulation of the formation control of three robots is perform, in which a optimal control and a receding horizon control is done to assure the validity of our approach.