The emergence of Software Defined Vehicles (SDVs) has introduced significant complexity in automotive system design, particularly for safety-critical domains such as braking. A key principle of SDV architecture is the centralization of control software, decoupled from sensing and actuation. When applied to Brake-by-Wire (BbW) systems, this leads to decentralized brake actuation that demands precise coordination across numerous distributed electronic components. The absence of mechanical backup in BbW systems further necessitates fail-operational redundancy, increasing system complexity and placing greater emphasis on rigorous system-level design validation. A comprehensive understanding of component interdependencies, failure propagation, and redundancy effectiveness is essential for optimizing such systems.
This paper presents a custom-built System Analysis Tool (SAT), along with a specialized methodology tailored for modeling and analyzing BbW architectures in the context of SDVs. The operation of the SAT is described in detail, and its application is demonstrated through illustrative examples derived from a representative BbW system model. The SAT enables systematic evaluation of individual component failures, their logical and functional interdependencies, and the cumulative impact of multiple simultaneous faults. It provides structured, data-driven insights that support early trade-off decisions between cost, complexity, and safety, and facilitates the generation of robust, traceable functional requirements. Additionally, the SAT quantifies the relationship between component failure rates, expressed in Failures in Time (FIT), and system-level performance degradation across multiple defined operational states.
By enabling a rigorous, model-based approach to design exploration and fault analysis, the SAT enhances system engineers' ability to validate fail-operational behavior, identify design weaknesses, and refine brake system architecture. This supports a more efficient development process for safety-critical systems and contributes to the overall reliability and performance of BbW implementations within SDV platforms.