9 research outputs found
Design of in-vehicle networked control system architectures through the use of new design to cost and weight processes : innovation report
Over the last forty years, the use of electronic controls within the automotive industry
has grown considerably. In-vehicle network technologies such as the Controller Area
Network (CAN) and Local Interconnect Network (LIN) are used to connect
Electronic Control Units (ECU) together, mainly to reduce the amount of wiring that
would be required if hardwired integration were used.
Modern passenger cars contain many networks, which means that for the
architecture designer, there is an almost overwhelming number of choices on how to
design/partition the system depending on factors such as cost, weight, availability of
ECUs, safety, Electro-Magnetic Compatibility (EMC) etc. Despite the increasing role
played by in-vehicle networks in automotive electrical architectures, its design could
currently be described as a “black art”. Not only is there an almost overwhelming
number of choices facing the designer, but there is currently a lack of a quantifiable
process to aid decision making and there is a dearth of published literature available.
NetGen is a software tool used to design CAN/J1939, LIN and FlexRay
networks. For the product to remain competitive, it is desirable to have novel features
over the competition. This report describes a body of work, the aim of which was to
research in-vehicle network design processes, and to provide an improvement to such
processes. The opportunities of customer projects and availability of customer
information resulted in the scope of the research focusing on the adoption of LIN
technology and whether the adoption of it could reduce the cost and weight of the
target architecture. The research can therefore be seen to address two issues: firstly
the general problem of network designers needing to design in-vehicle network based
architectures balancing the needs of many design targets such as cost, weight etc, and
secondly the commercial motivation to find novel features for the design tool, NetGen. The outcome of the research described in this report was the development of
design processes that can be used for the selection of low cost and weight automotive
electrical architectures using coarse information, such as that which would be easily
available at the very beginning of a vehicle design programme. The key benefit of
this is that a number of candidate networked architectures can be easily assessed for
their ability to reduce cost and weight of the electrical architecture
HardwaregestĂĽtzte Energieoptimierung von Elektrik/Elektronik-Architekturen durch adaptive Abschaltung von verteilten, eingebetteten Systemen
Mit der steigenden Bedeutung des Kraftstoffverbrauchs von Fahrzeugen geriet in den letzten Jahren auch die elektrische Leistungsaufnahme eines Fahrzeugs in den Blickpunkt. Diese ist durch den Zuwachs von Umfang und Komplexität von automobilen Elektrik/Elektronik-Systemen über die letzten Fahrzeuggenerationen hinweg stark angestiegen. Die vorliegende Arbeit befasst sich daher mit Ansätzen zur Energieoptimierung automobiler Elektrik/Elektronik-Architekturen aus Sicht eines Fahrzeugherstellers
Flexible management of bandwidth and redundancy in fieldbuses
Doutoramento em Engenharia ElectrotĂ©cnicaOs sistemas distribuĂdos embarcados (Distributed Embedded Systems – DES) tĂŞm sido usados ao longo dos Ăşltimos anos em muitos domĂnios de aplicação, da robĂłtica, ao controlo de processos industriais passando pela aviĂłnica e pelas aplicações veiculares, esperando-se que esta tendĂŞncia continue nos prĂłximos anos.
A confiança no funcionamento Ă© uma propriedade importante nestes domĂnios de aplicação, visto que os serviços tĂŞm de ser executados em tempo Ăştil e de forma previsĂvel, caso contrário, podem ocorrer danos econĂłmicos ou a vida de seres humanos poderá ser posta em causa.
Na fase de projecto destes sistemas Ă© impossĂvel prever todos os cenários de falhas devido ao nĂŁo determinismo do ambiente envolvente, sendo necessária a inclusĂŁo de mecanismos de tolerância a falhas.
Adicionalmente, algumas destas aplicações requerem muita largura de banda, que também poderá ser usada para a evolução dos sistemas, adicionandolhes novas funcionalidades.
A flexibilidade de um sistema é uma propriedade importante, pois permite a sua adaptação às condições e requisitos envolventes, contribuindo também para a simplicidade de manutenção e reparação. Adicionalmente, nos sistemas
embarcados, a flexibilidade também é importante por potenciar uma melhor utilização dos, muitas vezes escassos, recursos existentes.
Uma forma evidente de aumentar a largura de banda e a tolerância a falhas dos sistemas embarcados distribuĂdos Ă© a replicação dos barramentos do sistema. Algumas soluções existentes, quer comerciais quer acadĂ©micas,
propõem a replicação dos barramentos para aumento da largura de banda ou para aumento da tolerância a falhas. No entanto e quase invariavelmente, o propósito é apenas um, sendo raras as soluções que disponibilizam uma maior
largura de banda e um aumento da tolerância a falhas. Um destes raros exemplos é o FlexRay, com a limitação de apenas ser permitido o uso de dois
barramentos.
Esta tese apresentada e discute uma proposta para usar a replicação de barramentos de uma forma flexĂvel com o objectivo duplo de aumentar a
largura de banda e a tolerância a falhas. A flexibilidade dos protocolos propostos também permite a gestão dinâmica da topologia da rede, sendo o número de barramentos apenas limitado pelo hardware/software.
As propostas desta tese foram validadas recorrendo ao barramento de campo
CAN – Controller Area Network, escolhido devido à sua grande implantação no mercado. Mais especificamente, as soluções propostas foram implementadas e validadas usando um paradigma que combina flexibilidade com comunicações event-triggered e time-triggered: o FTT – Flexible Time- Triggered. No entanto, uma generalização para CAN nativo é também apresentada e discutida.
A inclusão de mecanismos de replicação do barramento impõe a alteração dos antigos protocolos de replicação e substituição do nó mestre, bem como a definição de novos protocolos para esta finalidade. Este trabalho tira partido da
arquitectura centralizada e da replicação do nĂł mestre para suportar de forma eficiente e flexĂvel a replicação de barramentos. Em caso de ocorrĂŞncia de uma falta num barramento (ou barramentos) que poderia provocar uma falha no sistema, os protocolos e componentes propostos nesta tese fazem com que o sistema reaja, mudando para um modo de funcionamento degradado. As
mensagens que estavam a ser transmitidas nos barramentos onde ocorreu a falta sĂŁo reencaminhadas para os outros barramentos.
A replicação do nĂł mestre baseia-se numa estratĂ©gia lĂder-seguidores (leaderfollowers),
onde o lĂder (leader) controla todo o sistema enquanto os seguidores (followers) servem como nĂłs de reserva. Se um erro ocorrer no nĂł
lĂder, um dos nĂłs seguidores passará a controlar o sistema de uma forma transparente e mantendo as mesmas funcionalidades.
As propostas desta tese foram tambĂ©m generalizadas para CAN nativo, tendo sido para tal propostos dois componentes adicionais. É, desta forma possĂvel ter as mesmas capacidades de tolerância a falhas ao nĂvel dos barramentos
juntamente com a gestão dinâmica da topologia de rede.
Todas as propostas desta tese foram implementadas e avaliadas. Uma
implementação inicial, apenas com um barramento foi avaliada recorrendo a uma aplicação real, uma equipa de futebol robótico onde o protocolo FTT-CAN foi usado no controlo de movimento e da odometria.
A avaliação do sistema com múltiplos barramentos foi feita numa plataforma de teste em laboratório. Para tal foi desenvolvido um sistema de injecção de faltas que permite impor faltas nos barramentos e nos nós mestre, e um sistema de medida de atrasos destinado a medir o tempo de resposta após a ocorrência de uma falta.Distributed embedded systems (DES) have been widely used in the last few decades in several application domains, from robotics, industrial process control, avionics and automotive. In fact, it is expectable that this trend will continue in the next years.
In some of these application fields the dependability requirements are very important since the fail to provide services in a timely and predictable manner
may cause important economic losses or even put humans in risk.
In the design phase it is impossible to predict all the possible scenarios of faults, due to the non deterministic behaviour of the surrounding environment.
In that way, the fault tolerance mechanisms must be included in the distributed embedded system to prevent failures occurrence.
Also, many application domains require a high available bandwidth to perform the desired functions, or to turn possible the scaling with the addition of new features.
The flexibility of a system also plays an important role, since it improves the capability to adapt to the surrounding world, and to the simplicity of the repair
and maintenance. The flexibility improves the efficiency of all the system by providing a way to efficiently manage the available resources. This is very important in embedded systems due to the limited resources often available.
A natural way to improve the bandwidth and the fault tolerance in distributed systems is to use replicated buses. Commercial and academic solutions propose the use of replicated fieldbuses for a single purpose only, either to improve the fault tolerance or to improve the available bandwidth, being the first the most common. One illustrative exception is FlexRay where the bus replica
can be used to improve the bandwidth of the overall system, besides enabling redundant communications. However, only one bus replica can be used.
In this thesis, a flexible bus replication scheme to improve both the dependability and the throughput of fieldbuses is presented and studied. It can
be applied to any number of replicated buses, provided the required hardware support is available. The flexible use of the replicated buses can achieve an also flexible management of the network topology.
This claim has been validated using the Controller Area Network (CAN) fieldbus, which has been chosen because it is widely spread in millions of
systems. In fact, the proposed solution uses a paradigm that combines flexibility, time and event triggered communication, that is the Flexible Time-
Triggered over CAN network (FTT-CAN). However, a generalization to native CAN is also presented and studied.
The inclusion of bus replication in FTT-CAN imposes not only new mechanisms but also changes of the mechanisms associated with the master replication, which has been already studied in previous research work. In this work, these
mechanisms were combined and take advantage of the centralized architecture and of the redundant masters to support an efficient and flexible bus
replication.
When considering the system operation, if a fault in the bus (or buses) occurs, and the consequent error leads to a system failure, the system reacts,
switching to a degraded mode, where the message flows that were transmitted in the faulty bus (or buses) change to the non-faulty ones.
The central node replication uses a leader-follower strategy, where the leader controls the system while the followers serve as backups. If an error occurs in
the leader, a backup will take the system control maintaining the system with the same functionalities.
The system has been generalized for native CAN, using two additional components that provide the same fault tolerance capabilities at the bus level,
and also enable the dynamic management of the network topology.
All the referred proposals were implemented and assessed in the scope of this work. The single bus version of FTT-CAN was assessed using a real
application, a robotic soccer team, which has obtained excellent results in international competitions. There, the FTT-CAN based embedded system has been applied in the low level control, where, mainly it is responsible for the
motion control and odometry.
For the case of the multiple buses system, the assessment was performed in a laboratory test bed. For this, a fault injector was developed in order to impose faults in the buses and in the central nodes. To measure the time reaction of the system, a special hardware has been developed: a delay measurement system. It is able to measure delays between two important time marks for posterior offline analysis of the obtained values
The Virtual Bus: A Network Architecture Designed to Support Modular-Redundant Distributed Periodic Real-Time Control Systems
The Virtual Bus network architecture uses physical layer switching and a combination of space- and time-division multiplexing to link segments of a partial mesh network together on schedule to temporarily form contention-free multi-hop, multi-drop simplex signalling paths, or 'virtual buses'. Network resources are scheduled and routed by a dynamic distributed resource allocation mechanism with self-forming and self-healing characteristics. Multiple virtual buses can coexist simultaneously in a single network, as the resources allocated to each bus are orthogonal in either space or time. The Virtual Bus architecture achieves deterministic delivery times for time-sensitive traffic over multi-hop partial mesh networks by employing true line-speed switching; delays of around 15ns at each switching point are demonstrated experimentally, and further reductions in switching delays are shown to be achievable. Virtual buses are inherently multicast, with delivery skew across multiple destinations proportional to the difference in equivalent physical length to each destination. The Virtual Bus architecture is not a purely theoretical concept; a small research platform has been constructed for development, testing and demonstration purposes
Nuove architetture di controllo distribuito per automazione di macchine da lavoro e agricole
The topics described in this thesis are inherent to safety-relevant systems architectures for heavy-duty machines and new communication protocols between ECUs for agricultural machines. The first topic is about the study, design and implementation of a new communication protocol for agricultural machines capable of high throughput, reliability and dynamicity to realize advanced automation functionalities for precision farming, keeping compatibility for current communication standards. The study starts from the analysis of the current standard for communication (ISO 11783) and on its limits in terms of feasible functionalities, due to the physical layer, the CAN Bus. Migration to different physical layers is mandatory and it has been done in automotive, industrial and aeronautics world, using Ethernet Fieldbuses. Several solutions based on CAN and Ethernet are analyzed, which made the adoption of TCP/IP Stack preferable due to its flexibility and customization capabilities for different purposes. Some tests are performed, in order to evaluate TCP/IP Stack behavior with typical traffic between ECUs on agricultural machines. The results confirm the feasibility of using TCP/IP Stack with Ethernet as a valid solution for superseding CAN. Later, the TCP/IP stack has been improved to fulfil ISO 11783 requirements. A proof-of-concept has been realized, made of a hybrid network with the new high throughput protocol based on Ethernet on one side, and the older one based on CAN on the other. The second theme is about the design and validation of a system architecture for safety-relevant applications on heavy-duty machines. The approach is based on designing an architecture made of hardware and software components, which is general purpose for different application. This approach is in contrast with the one proposed by the safety standards (ISO 13849, ISO 25119, IEC 61508), but can achieve the same goals, increasing the re-use of validated architectures
Systematic Approaches for Telemedicine and Data Coordination for COVID-19 in Baja California, Mexico
Conference proceedings info:
ICICT 2023: 2023 The 6th International Conference on Information and Computer Technologies
Raleigh, HI, United States, March 24-26, 2023
Pages 529-542We provide a model for systematic implementation of telemedicine within a large evaluation center for COVID-19 in the area of Baja California, Mexico. Our model is based on human-centric design factors and cross disciplinary collaborations for scalable data-driven enablement of smartphone, cellular, and video Teleconsul-tation technologies to link hospitals, clinics, and emergency medical services for point-of-care assessments of COVID testing, and for subsequent treatment and quar-antine decisions. A multidisciplinary team was rapidly created, in cooperation with different institutions, including: the Autonomous University of Baja California, the Ministry of Health, the Command, Communication and Computer Control Center
of the Ministry of the State of Baja California (C4), Colleges of Medicine, and the College of Psychologists. Our objective is to provide information to the public and to evaluate COVID-19 in real time and to track, regional, municipal, and state-wide data in real time that informs supply chains and resource allocation with the anticipation of a surge in COVID-19 cases. RESUMEN Proporcionamos un modelo para la implementaciĂłn sistemática de la telemedicina dentro de un gran centro de evaluaciĂłn de COVID-19 en el área de Baja California, MĂ©xico. Nuestro modelo se basa en factores de diseño centrados en el ser humano y colaboraciones interdisciplinarias para la habilitaciĂłn escalable basada en datos de tecnologĂas de teleconsulta de telĂ©fonos inteligentes, celulares y video para vincular hospitales, clĂnicas y servicios mĂ©dicos de emergencia para evaluaciones de COVID en el punto de atenciĂłn. pruebas, y para el tratamiento posterior y decisiones de cuarentena. Rápidamente se creĂł un equipo multidisciplinario, en cooperaciĂłn con diferentes instituciones, entre ellas: la Universidad AutĂłnoma de Baja California, la SecretarĂa de Salud, el Centro de Comando, Comunicaciones y Control Informático.
de la SecretarĂa del Estado de Baja California (C4), Facultades de Medicina y Colegio de PsicĂłlogos. Nuestro objetivo es proporcionar informaciĂłn al pĂşblico y evaluar COVID-19 en tiempo real y rastrear datos regionales, municipales y estatales en tiempo real que informan las cadenas de suministro y la asignaciĂłn de recursos con la anticipaciĂłn de un aumento de COVID-19. 19 casos.ICICT 2023: 2023 The 6th International Conference on Information and Computer Technologieshttps://doi.org/10.1007/978-981-99-3236-
Safety and Reliability - Safe Societies in a Changing World
The contributions cover a wide range of methodologies and application areas for safety and reliability that contribute to safe societies in a changing world. These methodologies and applications include: - foundations of risk and reliability assessment and management
- mathematical methods in reliability and safety
- risk assessment
- risk management
- system reliability
- uncertainty analysis
- digitalization and big data
- prognostics and system health management
- occupational safety
- accident and incident modeling
- maintenance modeling and applications
- simulation for safety and reliability analysis
- dynamic risk and barrier management
- organizational factors and safety culture
- human factors and human reliability
- resilience engineering
- structural reliability
- natural hazards
- security
- economic analysis in risk managemen