2002-01-0476 Model-Based Architecting for Reliability, Availability, and Maintainability Software in Automotive Applications

The importance of defining requirements correctly in the development process of software is well known in software industry. Since RAM(Reliability, Availability, and Maintainability) is a significant effectiveness element for the operation of automotive engine, it requires a thorough analysis during the design and testing of an engine. In this study, user requirements for the calculation of RAM and RG(Reliability Growth) were identified and documented by using a Model-Based Systems Engineering (MBSE) tool, RDD-100. The tool supports the traceability of each function to the corresponding requirement. Requirements were organized into behavior items such as RAM calculations, display, and data query and into non-behavior items such as input, output, and environment conditions. Additional requirements were derived if new functions are needed in the software even if the originating requirements did not exist in the early stage of the software development. Scenarios that describe the analysis of RAM and RG of the automotive engine were constructed to explain the activity and data flow among users, RAM software, and engine database. The toplevel architecture of this software was designed by allocating functions on the three simple components in the block diagram. The relationship in the requirements, functions, and architecture is traceable among each other. This approach in the development of engine software not only facilitates the design process but also provides an efficient configuration management approach to any change or improvement of the software during the life cycle. It also maintains the top-level architecture design knowledge captured during early development phase.