Hybrid architecture for autonomous navigation robots is presented in this paper. The principal future aim of this architecture is to achieve multi-robot convoy which must navigate in urban background, where autonomous vehicles have to track the desired trajectory while avoiding possible obstacles (walkers, other robots, etc.). Currently, we consider only the case of fixed obstacles. We propose to coordinate two continuous controllers (trajectory tracking and obstacle avoidance) by discrete events. However, hard switch from obstacle avoidance to trajectory following controller, may cause collision or undesired effects due to nonholonomic constraint or switching effects. Therefore, we introduce a third controller to overcome these drawbacks.