Component Based Design of Hybrid Systems: A Case Study on Concurrency and Coupling (Extended Version)

Werner Damm and Willem Hagemann and Eike Möhlmann and Astrid Rakow
In the search of design principles that allow compositional reasoning about safety and stability properties of hybrid controllers we examine a case study on a simplified driver assistance system for lane keeping and velocity control. We thereby target loosely coupled systems: the composed system has to accomplish a task that may depend on several of its subcomponents while little coordination between them is necessary. Our assistance system has to accomplish a comfortable centrifugal force, lane keeping and velocity control. This leads to an architecture composed of a velocity controller and a steering controller, where each controller has its local objectives and together they maintain a global objective. The steering controller makes time bounded promises about its steering, which the velocity controller uses for optimization. For this system, we deductively prove from the components' properties that the objectives of the composed system are accomplished.