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Balancing between dependability and cost-effectiveness is essential to promote X-by-Wire systems in the next decade. To achieve this goal, we have so far proposed a network centric architecture based on a concept of autonomous decentralized systems, where if one node fails, the remaining normal nodes autonomously execute a backup control to maintain the system's functionality, as well as a membership middleware indispensable to this architecture to ensure the consistency of the node status information among all nodes. In this work, we implemented membership middleware on a hardware and software platform equivalent to one assumed to be used in actual X-by-Wire systems. This paper describes the implementation details and performance evaluation result, and shows that membership middleware and a real-time critical application can coexist within one microcontroller.

Electronic controllers for powertrain systems are required to meet the demands for increased system performance and functionality at reasonable cost. It is indispensable to examine the solutions from a range of view points synthetically for cost optimization. This paper describes a cost-effective hardware and software architecture of the electronic controllers for powertrain systems. A new method for noise reduction of a switching regulator, and a low standby current wakeup solution are also discussed as further functions needed for high performance powertrain systems.

To detect difficult-to-find defects in automotive control systems, we have proposed a modeling method with a program slicing technique. In this method, a verifier adjusts the boundaries of source code to be extracted on a variable dependence graph, in a kind of data flow. We have developed software tools for this method and achieved a 35% decrease in total verification time on model checking. This paper provides some consideration on effective cases of the method from verification practices. There are two types of malfunction causes: one is the timing of processes (race conditions), and the other is complex logics. Each type requires different elements in external environment models. Furthermore, we propose regression verification based on the modeling method above, to further reduce verification time on model checking. The paper outlines tool extensions needed to realize regression verification.

X-by-Wire systems are expected to enhance vehicle driving performance and safety. This paper describes an electronic platform architecture for X-by-Wire systems that satisfies both cost-effectiveness and dependability. In the first part of this paper (Part 1), we have proposed a new electronic architecture based on a concept of autonomous decentralized systems. In the latter part (Part 2), the proposed architecture implementation to the actual vehicle control systems will be discussed. We clarify that, due to system level redundancy the proposed architecture provides, vehicle control systems can basically consist of low cost fail-silent nodes. Furthermore, for cost optimization, considering a tradeoff between hardware cost and fault detection coverage, we design a suitable hardware architecture for each node according to node function.

The X-By-Wire (XBW) is one of the promising technologies for integrated vehicle dynamics control system for the next-generation. The system, in view of ECU architecture, combines multiple ECUs by a high-speed. In this, however, the failure of one ECU leads to system-wide failure. To avoid it, all the ECUs have to be fault tolerant, which is not a realistic solution in terms of cost. We propose a concept for a cost-effective and fault tolerant vehicle control architecture for real-time and scalable X-by-Wire systems. The concept is based on the Autonomous Decentralized Systems [1][2]. The features of the proposed concept are a shared data-field, self-operation, self-check, and self-backup. The proposed architecture will realize a fault-tolerant system without making all the subsystems fault-tolerant.

X-by-Wire systems are expected to enhance vehicle driving performance and safety. Regarding the dependable and cost-effective electronic platform for X-by-Wire systems, we have so far proposed a network centric architecture based on a concept of autonomous decentralized systems. In this architecture, in case a certain node fails, the remaining normal nodes autonomously execute a backup control to maintain the system function. Following the concept proposal, in this study, we have designed the middleware for cluster node status monitoring because it is essential to identify the failed node accurately to execute the autonomous backup control. The middleware has been implemented on the FlexRay-based prototype brake-by-wire system. This paper describes the features of the middleware indispensable to the network centric X-by-Wire systems.