Selective integration of formal methods in the development of electronic control units

This paper introduces a dual approach for describing the software of embedded systems in motor vehicles. The approach divides the description into two parts, an operational model and a number of associated model properties. Starting from a tool-based software design with established structured methods that are basically suitable for the integration of mathematically precise techniques, proposals are made for the selective integration of formal methods into the description of properties of design components. By systematically checking these two views against each other it is possible to detect and eliminate inconsistencies and errors in the modelling at an early stage of development. The presented approach aims at applying the advantages of a more formal approach to the development of automotive software in an industrial setting. For evaluation purposes, the presented concepts are applied to the software of a cruise control system.