Using SysML for Modeling of Safety-Critical Software-Hardware Interfaces: Guidelines and Industry Experience

Safety-critical embedded systems often need to undergo a rigorous certification process to ensure that the safety risks associated with the use of the systems are adequately mitigated. Interfaces between software and hardware components (SW/HW interfaces) play a fundamental role in these systems by linking the systems' control software to either the physical hardware components or to a hardware abstraction layer. Subsequently, safety certification of embedded systems necessarily has to cover the SW/HW interfaces used in these systems. In this paper, we describe a Model Driven Engineering (MDE) approach based on the SysML language, targeted at facilitating the certification of SW/HW interfaces in embedded systems. Our work draws on our experience with maritime and energy systems, but the work should also apply to a broader set of domains, e.g., the automotive sector, where similar design principles are used for (SW/HW) interface design. Our approach leverages our previous work on the development of SysML-based modeling and analysis techniques for safety-critical systems. Specifically, we tailor the methodology developed in our previous work to the development of safety-critical interfaces, and provide step-by-step and practical guidelines aimed at providing the evidence necessary for arguing that the safety-related requirements of an interface are properly addressed by its design. We describe an application of our proposed guidelines to a representative safety-critical interface in the maritime and energy domain.