The paper presents the results of a research project that aimed at designing a fleet of autonomous omnidirectional mobile robots equipped with a conveyor segment for logistic applications in which humans and robots collaborate in the same area and that would require a minimum of additional fixed infrastructure for navigation. It presents the challenges addressed and the layered architecture for ensuring safe operation of each robot and a coordination system using a collection decentralized nodes based on Robot Operating System for obtaining a flexible, smart and scalable logistic system capable of handling and tracking delivery orders based on bar-code labeled packages routed between source fixed conveyor systems (outputs of the warehouse) and destination conveyor systems (the temporary storage for loading into trucks).