Enhancing Model-Based Development of Embedded Systems : Modeling, Simulation and Model-Transformation in an Auotmotive Context
Abstract: The increased usage of embedded computer systems in products like automobiles has not only introduced new innovations, additional safety and comfort but also increased the product and development complexity. Several model-based development (MBD) approaches have been proposed to support the management of such complexity. The thesis is aimed towards an integrated environment for MBD of automotive embedded systems. The envisioned environment features model exchange, and choice of modeling techniques, formalisms and tools in an efficient manner.The first contribution is an integration of EAST-ADL, an automotive specific ADL with a timed automata (TA) formalism for verifying embedded systems. The focus is mainly on EAST-ADL’s Timing Model (TM) and Behavior Description Annex (BDA). The TM is used for specifying a system’s timing related constraints such as delays and precedence. The BDA not only provides support for modeling behavior using a common formalism but also combines different behavior types for expressing logic, execution and error. The results are a) a formal interpretation of the TM through its transformation to TA, and b) an algorithm for transforming BDA to TA. While the former enables checking consistency between the artifacts of a TM the latter can be used for a holistic behavioral analysis.In the second contribution, different possibilities to realize EAST-ADL models by AUTOSAR software architecture (a standard for developing automotive embedded software) are studied. The main result is an enhanced mapping scheme between EAST-ADL and AUTOSAR. The findings can serve as guidelines for realizing configurations in EAST-ADL as AUTOSAR parameters.The third contribution addresses advanced embedded system features by evaluating the TM and TA for dynamic configuration mechanisms and studying Stateflow and SimEvents as alternatives for simulating architectural specifications based on EAST-ADL’s BDA. The results include a) an account of possibilities and issues related to the TM and TA integration studied in this thesis for dynamic configuration mechanisms, b) a comparison of Stateflow and SimEvents in terms of both underlying modeling formalisms and as tools and c) a discussion on possible future opportunities and issues for integrating EAST-ADL, SimEvents, Stateflow and timed automata for the envisioned integrated development environment.The work is supported by several case studies including a brake-by-wire system, an emergency braking system, a position and a fuel control system, an automatic drive train, and a dynamic reconfiguration scenario related to the relocation of a software component from a failed processing unit to a working one in a microprocessor-based distributed system.
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