This paper proposes a solution to the problem of coordinating multi-robot systems, which execute individually planned tasks in a shared workspace. The presented approach is a decoupled method that can coordinate the participants robots in on-line mode. The coordination is achieved through the adjustment of the time evolution of each robot along its original planned path according to the movements of the other robots to assure a collision free execution of their tasks. To assess the proposed approach a two robot system was used, and different tests were performed in graphical simulations as well as in real executions. Some examples are presented in the paper.