Automatic generation of discrete handlers of real-time continuous control tasks

International audienceWe present a novel technique for designing discrete, logical control loops, on top of continuous control tasks, ensuring logical safety properties of the tasks sequencings and mode changes. We define this new handler on top of the real-time executives built with the ORCCAD design environment for control systems, which is applied, e.g. to robotics and real-time networked control. It features structures of control tasks, each equipped with a local automaton, used for the reactive, event-based management of its activity and modes. The additional discrete handler manages the interactions between tasks, concerning, e.g., mutual exclusions, forbidden or imposed sequences. We use a new reactive programming language, with constructs for finite-state machines and data-flow nodes, and a mechanism of behavioral contracts, which involves discrete controller synthesis. The result is a discrete control loop, on top of the continuous control loops, all integrated in a coherent real-time architecture. Our approach is illustrated and validated experimentally with the case study of a robot arm