The paper presents a fail-safe mobility management and a collision prevention platform for a group of asynchronous cooperative mobile robots. The fail-safe platform consists of a time-free collision prevention protocol, which guarantees that no collision can occur between robots, independently of timeliness properties of the system, and even in the presence of timing errors in the environment. The collision prevention protocol is based on a distributed path reservation system. Each robot in the system knows the composition of the group, and can communicate with all robots of the group. A performance analysis of the protocol provides insights for a proper dimensioning of system parameters in order to maximize the average effective speed of the robots.