In this paper we propose a distributed architecture for intelligent robotic systems. The architecture is specific to this domain because it intends to provide support for this type of applications that share particular functional requirements: concurrent perception and action, task and plan execution, reasoning, "intelligent behaviours". The architecture also aims to improve re-usability and integration of different software components. It allows the transparent distribution of processes on different computers in a network to take advantage of the increased computational power and to overcome the vehicles on-board limitations. We focus on the related cognitive model, on the internal structure of the architecture and of its components. We also examine in detail the EIE protocol we defined to exchange information within the distributed system. Finally we indicate some experimental results.