Research On Methodology Of Model-Based Synthesis For Automotive Electronics Software

With the rapid development of information technology, embedded systems have permeated into every aspect of industries and lives. Automotive electronics is a typical field in which embedded systems are applied, and it has become the main motivation for the development of automotive techniques. As the core of automotive electronic systems, the automotive electronic control system plays an important role in improving the performance, safety, and reliability.Software for automotive electronic control system has stringent hard real-time requirements, and is constrained by system resources and energy. With the increasing complication of automotive electronic control systems and the pressure of shortening time to market, the current software development methodology become more and more difficult in fulfilling the automotive electronic control software's requirements for high complexity, high safety, low cost, short development periods. Model-based software development can efficiently control complexity, improve productivity, reduce the cost of developing and maintaining, and improve correctness, which make it become one of the important research fields in current embedded software development. Model synthesis, as a critical phase in model-based embedded software development, has important influence on fulfilling the non-functional constraints of embedded software and generating the correct embedded software. However, the existing model synthesis methodologies has the following problems: 1) they do not support complex transaction models; 2) they do not support the hybrid scheduling mode and the group-based scheduling mode; 3) they do not support the timing verification of complex transaction models under the hybrid scheduling mode and the group-based scheduling mode; 4) they do not consider the energy-saving problem. Therefore, it is difficult for them to fulfill the requirements of model synthesis in the model-based development for automotive electronic control software.This thesis researches the model synthesis problem when using automotive electronic control systems as the hardware platforms of implementation models, operating systems compatible with OSEK standard, a wildly accepted standard in automotive electronic field as software platforms, complex transaction model as task models. This thesis focuses on the model synthesis problems in uniprocessor environment, distributed environment and energy-efficient model synthesis. This research provides supports for automatic model synthesis in the development of automotive electronics software.The main contents and contributions of this thesis are as follows.First, it presents the MOSAES, a theoretic framework of model synthesis for the development of model-based automotive electronics software. This thesis describes the relationship between MOSAES and SmartOSEK IDE V3.5 (which is ongoing), and defines the models used in MOSAES, such as the structural model, the platform model, the implementation model, and the constraint model, which provide a clear context for model synthesis.Second, it presents the model synthesis methodology for uniprocessor environment with the goal of optimizing Critical Scaling Factors. This thesis extends the HKL algorithm and presents the method of timing verification when using 1-M and M-1 sharing under the hybrid scheduling mode, and the method of timing verification when using M-1 sharing under the group-based scheduling mode. It also presents the workflow of model synthesis under the hybrid scheduling mode and the group-based scheduling mode for uniprocessor environment. During model synthesis, we use timing analysis to verify the timing constraints, use the Simulated Annealing algorithm to explore priority assignment and optimizing Critical Scaling Factors, merge tasks according to the interference relations among tasks in order to reduce system overheads while keeping the results of timing verification.Third, it presents the model synthesis methodology for distributed environment with the goal of meeting multiple resource constraints. This methodology includes two steps: component assignment and implementation model generation. It first assigns components into processors under the conditions that satisfy computation resource and memory resource constraints, and keep the balance of computation density among processors. And then it generates implementation models while satisfying timing constraints. It is a backtracking process between component assignment and implementation model generation. Morever, this thesis presents the timing verification method for non-consecutive task segments under the hybrid scheduling mode and the group-based scheduling mode to meet the requirements of timing verification in distributed environment.Last, it presents the energy-efficient model synthesis methodology. It first presents the HDVS algorithm under the Linear Transactions with Fixed Priorities model. And then, on the basis of energy-saving theory, this thesis analyzes the characteristics of structural models and the influence of scheduling modes on the classification of transaction types and tasks execution. This thesis extends the model synthesis methodology for uniprocessor environment, and integrates energy efficiency into MOSAES for uniprocessor environment.This thesis was supported in part by the 863 National High Technology Program of China.