Distributed Embedded Control Systems

This fascinating new work comes complete with more than 100 illustrations and a detailed practical prototype. It explores the domains encountered when designing a distributed embedded computer control system as an integrated whole. Basic issues about real-time systems and their properties, especially safety, are examined first. Then, system and hardware architectures are dealt with, along with programming issues, embodying desired properties, basic language subsets, object orientation and language support for hardware and software specifications.

"This book addresses the development of reconfigurable embedded control systems and describes various problems in this important research area, which include static and dynamic (manual or automatic) reconfigurations, multi-agent architectures, modeling and verification, component-based approaches, architecture description languages, distributed reconfigurable architectures, real-time and low power scheduling, execution models, and the implementation of such systems"--

This volume is the proceedings of a workshop organized by General Motors research and development laboratory in Bangalore, India. It was the first of its kind to be run by an automotive major to bring together the leaders in the field of embedded systems development to present state-of-the-art work, and to discuss future strategies for addressing the increasing complexity of embedded control systems. The workshop consisted of invited talks given by leading experts and researchers from academic and industrial organizations. It covered all areas of embedded systems development.

Embedded systems are becoming one of the major driving forces in computer science. Furthermore, it is the impact of embedded information technology that dictates the pace in most engineering domains. Nearly all technical products above a certain level of complexity are not only controlled but increasingly even dominated by their embedded computer systems. Traditionally, such embedded control systems have been implemented in a monolithic, centralized way. Recently, distributed solutions are gaining increasing importance. In this approach, the control task is carried out by a number of controllers distributed over the entire system and connected by some interconnect network, like fieldbuses. Such a distributed embedded system may consist of a few controllers up to several hundred, as in today's top-range automobiles. Distribution and parallelism in embedded systems design increase the engineering challenges and require new development methods and tools. This book is the result of the International Workshop on Distributed and Parallel Embedded Systems (DIPES'98), organized by the International Federation for Information Processing (IFIP) Working Groups 10.3 (Concurrent Systems) and 10.5 (Design and Engineering of Electronic Systems). The workshop took place in October 1998 in Schloss Eringerfeld, near Paderborn, Germany, and the resulting book reflects the most recent points of view of experts from Brazil, Finland, France, Germany, Italy, Portugal, and the USA. The book is organized in six chapters: `Formalisms for Embedded System Design': IP-based system design and various approaches to multi-language formalisms. `Synthesis from Synchronous/Asynchronous Specification': Synthesis techniques based on Message Sequence Charts (MSC), StateCharts, and Predicate/Transition Nets. `Partitioning and Load-Balancing': Application in simulation models and target systems. `Verification and Validation': Formal techniques for precise verification and more pragmatic approaches to validation. `Design Environments' for distributed embedded systems and their impact on the industrial state of the art. `Object Oriented Approaches': Impact of OO-techniques on distributed embedded systems. £/LIST£ This volume will be essential reading for computer science researchers and application developers.

Today, many embedded or cyber-physical systems, e.g., in the automotive domain, comprise several control applications, sharing the same platform. It is well known that such resource sharing leads to complex temporal behaviors that degrades the quality of control, and more importantly, may even jeopardize stability in the worst case, if not properly taken into account. In this thesis, we consider embedded control or cyber-physical systems, where several control applications share the same processing unit. The focus is on the control-scheduling co-design problem, where the controller and scheduling parameters are jointly optimized. The fundamental difference between control applications and traditional embedded applications motivates the need for novel methodologies for the design and optimization of embedded control systems. This thesis is one more step towards correct design and optimization of embedded control systems. Offline and online methodologies for embedded control systems are covered in this thesis. The importance of considering both the expected control performance and stability is discussed and a control-scheduling co-design methodology is proposed to optimize control performance while guaranteeing stability. Orthogonal to this, bandwidth-efficient stabilizing control servers are proposed, which support compositionality, isolation, and resource-efficiency in design and co-design. Finally, we extend the scope of the proposed approach to non-periodic control schemes and address the challenges in sharing the platform with self-triggered controllers. In addition to offline methodologies, a novel online scheduling policy to stabilize control applications is proposed.

From Model-Driven Design to Resource Management for Distributed Embedded Systems presents 16 original contributions and 12 invited papers presented at the Working Conference on Distributed and Parallel Embedded Systems - DIPES 2006, sponsored by the International Federation for Information Processing - IFIP. Coverage includes model-driven design, testing and evolution of embedded systems, timing analysis and predictability, scheduling, allocation, communication and resource management in distributed real-time systems.

Optimal Design of Distributed Control and Embedded Systems focuses on the design of special control and scheduling algorithms based on system structural properties as well as on analysis of the influence of induced time-delay on systems performances. It treats the optimal design of distributed and embedded control systems (DCESs) with respect to communication and calculation-resource constraints, quantization aspects, and potential time-delays induced by the associated communication and calculation model. Particular emphasis is put on optimal control signal scheduling based on the system state. In order to render this complex optimization problem feasible in real time, a time decomposition is based on periodicity induced by the static scheduling is operated. The authors present a co-design approach which subsumes the synthesis of the optimal control laws and the generation of an optimal schedule of control signals on real-time networks as well as the execution of control tasks on a single processor. The authors also operate a control structure modification or a control switching based on a thorough analysis of the influence of the induced time-delay system influence on stability and system performance in order to optimize DCES performance in case of calculation and communication resource limitations. Although the richness and variety of classes of DCES preclude a completely comprehensive treatment or a single “best” method of approaching them all, this co-design approach has the best chance of rendering this problem feasible and finding the optimal or some sub-optimal solution. The text is rounded out with references to such applications as car suspension and unmanned vehicles. Optimal Design of Distributed Control and Embedded Systems will be of most interest to academic researchers working on the mathematical theory of DCES but the wide range of environments in which they are used also promotes the relevance of the text for control practitioners working in the avionics, automotive, energy-production, space exploration and many other industries.

This book describes a model-based development approach for globally-asynchronous locally-synchronous distributed embedded controllers. This approach uses Petri nets as modeling formalism to create platform and network independent models supporting the use of design automation tools. To support this development approach, the Petri nets class in use is extended with time-domains and asynchronous-channels. The authors’ approach uses models not only providing a better understanding of the distributed controller and improving the communication among the stakeholders, but also to be ready to support the entire lifecycle, including the simulation, the verification (using model-checking tools), the implementation (relying on automatic code generators), and the deployment of the distributed controller into specific platforms. Uses a graphical and intuitive modeling formalism supported by design automation tools; Enables verification, ensuring that the distributed controller was correctly specified; Provides flexibility in the implementation and maintenance phases to achieve desired constraints (high performance, low power consumption, reduced costs), enabling porting to different platforms using different communication nodes, without changing the underlying behavioral model.