Academic literature on the topic 'INTEGRATED MODULAR AVIONICS'

The purpose of this research is to investigate fault management methodologies within Integrated Modular Avionics (IMA) systems, and develop techniques by which the use of dynamic reconfiguration can be implemented to restore higher levels of systems redundancy in the event of a systems fault. A proposed concept of dynamic configuration has been implemented on a test facility that allows controlled injection of common faults to a representative IMA system. This facility allows not only the observation of the response of the system management activities to manage the fault, but also analysis of real time data across the network to ensure distributed control activities are maintained. IMS technologies have evolved as a feasible direction for the next generation of avionic systems. Although federated systems are logical to design, certify and implement, they have some inherent limitations that are not cost beneficial to the customer over long life-cycles of complex systems, and hence the fundamental modular design, i.e. common processors running modular software functions, provides a flexibility in terms of configuration, implementation and upgradability that cannot be matched by well-established federated avionic system architectures. For example, rapid advances of computing technology means that dedicated hardware can become outmoded by component obsolescence which almost inevitably makes replacements unavailable during normal life-cycles of most avionic systems. To replace the obsolete part with a newer design involves a costly re-design and re-certification of any relevant or interacting functions with this unit. As such, aircraft are often known to go through expensive mid-life updates to upgrade all avionics systems. In contrast, a higher frequency of small capability upgrades would maximise the product performance, including cost of development and procurement, in constantly changing platform deployment environments. IMA is by no means a new concept and work has been carried out globally in order to mature the capability. There are even examples where this technology has been implemented as subsystems on service aircraft. However, IMA flexible configuration properties are yet to be exploited to their full extent; it is feasible that identification of faults or failures within the system would lead to the exploitation of these properties in order to dynamically reconfigure and maintain high levels of redundancy in the event of component failure. It is also conceivable to install redundant components such that an IMS can go through a process of graceful degradation, whereby the system accommodates a number of active failures, but can still maintain appropriate levels of reliability and service. This property extends the average maintenance-free operating period, ensuring that the platform has considerably less unscheduled down time and therefore increased availability. The content of this research work involved a number of key activities in order to investigate the feasibility of the issues outlined above. The first was the creation of a representative IMA system and the development of a systems management capability that performs the required configuration controls. The second aspect was the development of hardware test rig in order to facilitate a tangible demonstration of the IMA capability. A representative IMA was created using LabVIEW Embedded Tool Suit (ETS) real time operating system for minimal PC systems. Although this required further code written to perform IMS middleware functions and does not match up to the stringent air safety requirements, it provided a suitable test bed to demonstrate systems management capabilities. The overall IMA was demonstrated with a 100kg scale Maglev vehicle as a test subject. This platform provides a challenging real-time control problem, analogous to an aircraft flight control system, requiring the calculation of parallel control loops at a high sampling rate in order to maintain magnetic suspension. Although the dynamic properties of the test rig are not as complex as a modern aircraft, it has much less stringent operating requirements and therefore substantially less risk associated with failure to provide service. The main research contributions for the PhD are: 1. A solution for the dynamic reconfiguration problem for assigning required systems functions (namely a distributed, real-time control function with redundant processing channels) to available computing resources whilst protecting the functional concurrency and time critical needs of the control actions. 2. A systems management strategy that utilises the dynamic reconfiguration properties of an IMA System to restore high levels of redundancy in the presence of failures. The conclusion summarises the level of success of the implemented system in terms of an appropriate dynamic reconfiguration to the response of a fault signal. In addition, it highlights the issues with using an IMA to as a solution to operational goals of the target hardware, in terms of design and build complexity, overhead and resources.

Avionics system manufacturers are currently facing the problem of developing highly-integrated systems under economic pressures. In this scenario, the empirical approach, characterized by trial and error techniques, is not adequate since the correction of design flaws is often related to expensive re-work and schedule overruns. The evolution of airborne systems toward Integrated Modular Avionics (IMA) pushes the need for advanced methods that could enforce correctness of complex designs while minimizing the chances of introducing errors. Considering this problem, this work proposes a systematic conceptual design strategy based on formal methods, aiming at improving the development processes for IMA systems. The basic idea is to concentrate efforts on the construction, simulation, and formal analysis of a mathematical model for the new system at early development lifecycle phases. The proposed approach was exercised on a case study of practical avionics project in order to evaluate the drawbacks and advantages. Results suggest that this work could contribute to the aeronautics industry by offering alternative means to cope with complexity in modern avionics projects.

<p>The Integrated Modular Avionics architecture , IMA, provides means for runningmultiple safety-critical applications on the same hardware. ARINC 653 is aspecification for this kind of architecture. It is a specification for space and timepartition in safety-critical real-time operating systems to ensure each application’sintegrity. This Master thesis describes how databases can be implementedand used in an ARINC 653 system. The addressed issues are interpartitioncommunication, deadlocks and database storage. Two alternative embeddeddatabases are integrated in an IMA system to be accessed from multiple clientsfrom different partitions. Performance benchmarking was used to study the differencesin terms of throughput, number of simultaneous clients, and scheduling.Databases implemented and benchmarked are SQLite and Raima. The studiesindicated a clear speed advantage in favor of SQLite, when Raima was integratedusing the ODBC interface. Both databases perform quite well and seem to begood enough for usage in embedded systems. However, since neither SQLiteor Raima have any real-time support, their usage in safety-critical systems arelimited. The testing was performed in a simulated environment which makesthe results somewhat unreliable. To validate the benchmark results, furtherstudies must be performed, preferably in a real target environment.The Integrated Modular Avionics architecture , IMA, provides means for runningmultiple safety-critical applications on the same hardware. ARINC 653 is aspecification for this kind of architecture. It is a specification for space and timepartition in safety-critical real-time operating systems to ensure each application’sintegrity. This Master thesis describes how databases can be implementedand used in an ARINC 653 system. The addressed issues are interpartitioncommunication, deadlocks and database storage. Two alternative embeddeddatabases are integrated in an IMA system to be accessed from multiple clientsfrom different partitions. Performance benchmarking was used to study the differencesin terms of throughput, number of simultaneous clients, and scheduling.Databases implemented and benchmarked are SQLite and Raima. The studiesindicated a clear speed advantage in favor of SQLite, when Raima was integratedusing the ODBC interface. Both databases perform quite well and seem to begood enough for usage in embedded systems. However, since neither SQLiteor Raima have any real-time support, their usage in safety-critical systems arelimited. The testing was performed in a simulated environment which makesthe results somewhat unreliable. To validate the benchmark results, furtherstudies must be performed, preferably in a real target environment.</p>

Nous nous intéressons dans cette thèse à la maîtrise de processeurs multi-cœurs COTS dans le but de les rendre utilisables dans des équipements avioniques, qui ont des exigences temps réelles dures. L’objectif est de permettre l'application de méthodes connues d’évaluation de pire temps d’exécution (WCET) sur un ensemble de tâches représentatif d’applications avioniques. Au cours de leur exécution, les tâches exécutées sur différents cœurs vont accéder simultanément à des ressources matérielles qui sont partagées entre les cœurs, en particulier la mémoire principale. Cela pourra entraîner des mises en attente de certains accès que l'on qualifie d'interférences. Ces interférences peuvent avoir un impact élevé sur le temps d'exécution du logiciel embarqué. Sur un processeur COTS, qui est acheté dans le commerce et vise un marché plus large que l'avionque, cet impact n'est pas borné. Nous cherchons à garantir l'absence d'interférences grâce à des moyens logiciels, dans la mesure où les processeurs COTS ne proposent pas de mécanismes adéquats au niveau matériel. Nous cherchons à étendre des concepts de logiciel déterministe de telle sorte à les rendre compatibles avec un objectif de réutilisation de logiciel existant. A cet effet, nous introduisons la notion de logiciel de contrôle, qui est un élément fonctionnellement neutre, répliqué sur tous les cœurs, et qui contrôle les dates des accès des cœurs aux ressources communes de telle sorte à offrir une isolation temporelle entre ces accès. Nous étudions dans cette thèse le problème de faisabilité d'un logiciel de contrôle sur un processeur COTS, et de son efficacité vis à vis d'applications avioniques<br>We focus in this thesis on issues related to COTS multi-core processors mastering, especially regarding hard real-time constraints, in order to enable their usage in future avionics equipment. We aim at applying existing Worst Case Execution Time (WCET) evaluation methods on a set of tasks similar to those we can find in avionics software. At runtime, tasks executed among different cores are likely to access hardware resources at the same time, e.g. the main memory. It may lead to additional delays due to hardware contention, called “interferences”. Interferences slow down embedded software within ranges that may be important. Additionnally, no bound has been established for their impact on WCET when using COTS processors, that target larger markets than avionics. We try to provide guarantees that all interferences are eliminated through software, as COTS processors do not provide adequate mechanisms at hardware level. We extend deterministic software concepts that have been developed in the state of the art, in order to make them compliant with the use of legacy software. We introduce the concept of "control software", which is functionnaly neutral, is replicated among all cores, and performs active control of core's accesses to shared resources, so that concurrent accesses are temporally isolated. We formalize and study in this thesis the problem of control software feasibility on COTS processors, and questions of efficiency with regard to legacy avionics software

Owing to advancements in component re-use technology, component-based software development (CBSD) has come a long way in developing complex commercial software systems while reducing software development time and cost. However, assembling distributed resource-constrained and safety-critical systems using current assembly techniques is a challenge. Within complex systems when there are numerous ways to assemble the components unless the software architecture clearly defines how the components should be composed, determining the correct assembly that satisfies the system assembly constraints is difficult. Component technologies like CORBA and .NET do a very good job of integrating components, but they do not automate component assembly; it is the system developer's responsibility to ensure thatthe components are assembled correctly. In this thesis, we first define a component-based system assembly (CBSA) technique called "Constrained Component Assembly Technique" (CCAT), which is useful when the system has complex assembly constraints and the system architecture specifies component composition as assembly constraints. The technique poses the question: Does there exist a way of assembling the components that satisfies all the connection, performance, reliability, and safety constraints of the system, while optimizing the objective constraint? To implement CCAT, we present a powerful framework called "CoBaSA". The CoBaSA framework includes an expressive language for declaratively describing component functional and extra-functional properties, component interfaces, system-level and component-level connection, performance, reliability, safety, and optimization constraints. To perform CBSA, we first write a program (in the CoBaSA language) describing the CBSA specifications and constraints, and then an interpreter translates the CBSA program into a satisfiability and optimization problem. Solving the generated satisfiability and optimization problem is equivalent to answering the question posed by CCAT. If a satisfiable solution is found, we deduce that the system can be assembled without violating any constraints. Since CCAT and CoBaSA provide a mechanism for assembling systems that have complex assembly constraints, they can be utilized in several industries like the avionics industry. We demonstrate the merits of CoBaSA by assembling an actual avionic system that could be used on-board a Boeing aircraft. The empirical evaluation shows that our approach is promising and can scale to handle complex industrial problems.

Nous nous intéressons dans cette thèse à la maîtrise de processeurs multi-cœurs COTS dans le but de les rendre utilisables dans des équipements avioniques, qui ont des exigences temps réelles dures. L’objectif est de permettre l'application de méthodes connues d’évaluation de pire temps d’exécution (WCET) sur un ensemble de tâches représentatif d’applications avioniques. Au cours de leur exécution, les tâches exécutées sur différents cœurs vont accéder simultanément à des ressources matérielles qui sont partagées entre les cœurs, en particulier la mémoire principale. Cela pourra entraîner des mises en attente de certains accès que l'on qualifie d'interférences. Ces interférences peuvent avoir un impact élevé sur le temps d'exécution du logiciel embarqué. Sur un processeur COTS, qui est acheté dans le commerce et vise un marché plus large que l'avionque, cet impact n'est pas borné. Nous cherchons à garantir l'absence d'interférences grâce à des moyens logiciels, dans la mesure où les processeurs COTS ne proposent pas de mécanismes adéquats au niveau matériel. Nous cherchons à étendre des concepts de logiciel déterministe de telle sorte à les rendre compatibles avec un objectif de réutilisation de logiciel existant. A cet effet, nous introduisons la notion de logiciel de contrôle, qui est un élément fonctionnellement neutre, répliqué sur tous les cœurs, et qui contrôle les dates des accès des cœurs aux ressources communes de telle sorte à offrir une isolation temporelle entre ces accès. Nous étudions dans cette thèse le problème de faisabilité d'un logiciel de contrôle sur un processeur COTS, et de son efficacité vis à vis d'applications avioniques<br>We focus in this thesis on issues related to COTS multi-core processors mastering, especially regarding hard real-time constraints, in order to enable their usage in future avionics equipment. We aim at applying existing Worst Case Execution Time (WCET) evaluation methods on a set of tasks similar to those we can find in avionics software. At runtime, tasks executed among different cores are likely to access hardware resources at the same time, e.g. the main memory. It may lead to additional delays due to hardware contention, called “interferences”. Interferences slow down embedded software within ranges that may be important. Additionnally, no bound has been established for their impact on WCET when using COTS processors, that target larger markets than avionics. We try to provide guarantees that all interferences are eliminated through software, as COTS processors do not provide adequate mechanisms at hardware level. We extend deterministic software concepts that have been developed in the state of the art, in order to make them compliant with the use of legacy software. We introduce the concept of "control software", which is functionnaly neutral, is replicated among all cores, and performs active control of core's accesses to shared resources, so that concurrent accesses are temporally isolated. We formalize and study in this thesis the problem of control software feasibility on COTS processors, and questions of efficiency with regard to legacy avionics software

Le domaine avionique a été transformé par l'apparition des architectures modulaires intégrées (IMA). Celles-ci définissent un support d'exécution et de communication standard et mutualisé afin de réduire la complexité de l'architecture physique. Cependant, du fait du partage des ressources, cette démarche introduit une plus grande complexité lors de la conception et de l'intégration des applications ce qui implique d'assister les concepteurs avec des outils dédiés. La présente thèse contribue à cet effort en se focalisant sur deux problèmes d'allocation de ressources : i) le problème de l'ordonnancement multiprocesseur de tâches strictement périodiques et ii) le problème du routage des messages échangés entre les fonctions avioniques. Le premier problème a été formalisé sous la forme d'un programme linéaire en nombres entiers afin de garantir un potentiel maximum d'évolution sur les durées d'exécutions des traitements. L'inefficacité d'une approche exacte pour des instances de grande taille, nous a conduit à développer une heuristique originale s'inspirant de la théorie des jeux couplée avec un algorithme multi-start. Le routage est formalisé sous la forme d'un problème d'optimisation sur la charge maximum des liens. Deux propositions sont faites pour le résoudre, l'une, exacte, est basée sur une formulation nœud-lien, et la seconde est une heuristique à deux niveaux basé sur une formulation lien-chemin. Mots-Clés en français : ordonnancement temps-réel, optimisation, systèmes avioniques, architectures modulaires intégrées, tâches strictement périodique, théorie de jeux, routage des liens virtuels