This paper describes a software architecture aimed at the development of complex robotic applications with stringent real-time constraints. The proposed methodology is based on a modular design approach, in which high-level processes are developed from elementary sensory-motor activities, carried our at lower layers of a hierarchical control system. The control software is organized in a number of layers, which add new capabilities to the robot system and allow the user to program an application at different levels of abstraction. At the lowest layer, the execution of all computational activities is supported by a hard real-time kernel, which provides predictable scheduling of periodic and aperiodic tasks. The flexibility of the proposed approach is shown through real robotic applications.