Improving transferability between different engineering stages in the development of automated material flow modules

For improving flexibility and robustness of the engineering of automated production systems (aPS) in case of extending, reducing or modifying parts, several approaches propose an encapsulation and clustering of related functions, e.g. from the electrical, mechanical or software engineering, based on a modular architecture. Considering the development of these modules, there are different stages, e.g. module planning or functional engineering, which have to be completed. A reference model that addresses the different stages for the engineering of aPS is proposed by AutomationML. Due to these different stages and the integration of several engineering disciplines, e.g. mechanical, electrical/electronic or software engineering, information not limited to one discipline are stored redundantly increasing the effort to transfer information and the risk of inconsistency. Although, data formats for the storage and exchange of plant engineering information exist, e.g. AutomationML, fixed domain specific structures and relations of the information, e.g. for automated material flow systems (aMFS), are missing. This paper presents the integration of a meta model into the development of modules for aMFS to improve the transferability and consistency of information between the different engineering stages and the increasing level of detail from the coarse-grained plant planning to the fine-grained functional engineering.Comment: 11 pages, https://ieeexplore.ieee.org/abstract/document/7499821

Application of model-based design tool X2C in induction machine vector control

Open source software tools for model-based design of embedded control systems represent a new method for rapid development and testing of advanced control structures in modern electric drives. The new concept of one of those tools, X2C, is presented in this paper, and in order to evaluate its performance in the development of complex control systems, it is applied to implement induction machine vector control. Based on the simulation model of the drive developed in PLECS, the parameters of the controllers were determined. The algorithm for the vector control of the induction machine was developed in X2C, implemented on the digital signal processor and applied to the real system. The system was tested during the no-load acceleration, deceleration, and reversing of the motor, while measuring the electrical and mechanical variables. Finally, the quantitative comparison of the experimental results and the results obtained by the equivalent simulations, based on the Integral Squared Error criterion, revealed that these results were well matched. This finding suggested that the control system was successfully implemented, thereby confirming the effectiveness of X2C tool in this particular type of application. With this work it has been shown that a transition from simulation to actual environment is rapidly achieved, with a simple verification of implemented methods accompanying the process. Realization of this work is a step forward in the utilization of open source software packages for implementation of induction machine vector control with the purpose of rapid verification of simulation models

Cyber-Physical Embedded Systems with Transient Supervisory Command and Control: A Framework for Validating Safety Response in Automated Collision Avoidance Systems

The ability to design and engineer complex and dynamical Cyber-Physical Systems (CPS) requires a systematic view that requires a definition of level of automation intent for the system. Since CPS covers a diverse range of systemized implementations of smart and intelligent technologies networked within a system of systems (SoS), the terms “smart” and “intelligent” is frequently used in describing systems that perform complex operations with a reduced need of a human-agent. The difference between this research and most papers in publication on CPS is that most other research focuses on the performance of the CPS rather than on the correctness of its design. However, by using both human and machine agency at different levels of automation, or autonomy, the levels of automation have profound implications and affects to the reliability and safety of the CPS. The human-agent and the machine-agent are in a tidal lock of decision-making using both feedforward and feedback information flows in similar processes, where a transient shift within the level of automation when the CPS is operating can have undesired consequences. As CPS systems become more common, and higher levels of autonomy are embedded within them, the relationship between human-agent and machine-agent also becomes more complex, and the testing methodologies for verification and validation of performance and correctness also become more complex and less clear. A framework then is developed to help the practitioner to understand the difficulties and pitfalls of CPS designs and provides guidance to test engineering design of soft computational systems using combinations of modeling, simulation, and prototyping

Estudo do impacto de transientes elétricos em protocolos de comunicação em sistemas embarcados

O aumento da complexidade e responsabilidade dos dispositivos embarcados nos veículos hoje, tem orientado os esforços no desenvolvimento de sistemas de controle para que estes sejam mais rápidos, precisos, robustos e principamente seguros. Com isso, estes dispositivos estão levando os protocolos de comunicação a um patamar inédito de exigência, tanto no quesito de capacidade como confiabilidade. Protocolos como CAN, CAN-FD e FlexRay entre outros, tem sido utilizados devido às suas características de segurança e a capacidade de atender aos requisitos temporais dos diversos circuitos embarcados. O desenvolvimento e utilização cada vez mais frequente de dispositivos focados em segurança, fazem com que a comunicação entre os diversos componentes destes dispositivos seja exigida ao máximo, levando à necessidade de respostas confiáveis ao extremo. Sistemas como freios ABS, suspensão ativa, frenagem autonoma de emergência, controle de velocidade e distância adaptativo, entre outros, que envolvem várias ECUs distribuídas ao longo do veículo, dispões de frações de segundo para a reação do sistema, entre o sinal de entrada e a atuação correspondente, demandando uma comunicação segura e tolerante à falhas. Os veículos hoje estão passando por grandes mudanças conceituais, trazendo cada vez mais elementos onde o funcionamento demanda mais energia das fontes de alimentação. Diversos sistemas existentes nos veículos geram ruídos como os Transientes Elétricos Rápidos, ou "Electric Fast Transient" (EFT), que estão presentes nas mais simples operações cotidianas do veículo, como ligar e desligar o farol, o ar condicionado, o limpador de para brisas, ou mesmo o acionamento de iluminação diurna (DRL), etc. Neste trabalho foram realizados diversos ensaios, utilizando ECUs com diferentes funções e protocolos, para identificar a susceptibilidade dos referidos sistemas e os protocolos à presença destes ruídos. Visando atender às normas IEC 62228 e a ISO26262, este trabalho demandou o projeto e construção de dois circuitos eletrônicos diferentes, um circuito observando os dados de tempos de subida e de descida (rise and fall time) dos pulsos de EFT, e outro observando a arquitetura do layout da placa de circuito impresso (PCB), as suas entradas, saídas, componentes, etc. Estes ensaios visaram identificar o quanto estes protocolos são suscetíveis à estes tipos de ruídos, utilizando métricas de análise baseadas nos tempos de latência e variação de jitter dos pacotes de comunicação.The increasing complexity and accountability of embedded devices in vehicles today has driven efforts to develop control systems to make them faster, accuratest, safest, robustest. Thus, these devices are taking communication protocols to an unprecedented level of demand, both in terms of capacity and reliability. Protocols such as CAN, CANFD and FlexRay among others have been used due to their safety characteristics and the ability to meet the time requirements of various embedded circuits. The increasing development and use of safety-focused devices, means that communication between the various components of these devices is required to the utmost, leading to the need for extremely reliable responses. Systems such as ABS brakes, active suspension, autonomous emergency braking, adaptative cruise control, among others, which involve various ECUs distributed throughout the vehicle, have milliseconds for system reaction, between input signal and concrete actuation, requiring safe and failure tolerant communication. Vehicles today are undergoing major conceptual changes, bringing more and more elements whose operation require more energy from power supplies. These systems generate noise such as "Electric Fast Transient" (EFT), which are present in the simplest daily operations of the vehicle, such as turning the headlight on, the air conditioner, the windscreen wiper, or even the daytime running light (DRL), etc. In this work several tests were carried out, using different ECUs with different functions and different protocols to identify the susceptibility of these systems and the protocols to these noises. In order to comply with IEC 62228 and ISO 26262 standards, this work required the design and construction of two different electronic circuits, one circuit observing the rise and fall time data of the EFT pulses, and the other observing the architecture of the printed circuit board (PCB) layout, its inputs and outputs, components, etc. These tests aimed to identify how susceptible these protocols are to these types of noise, using analysis metrics based on latency time and jitter variation of communication packets

Metodologia para teste e análise de degradação de desempenho em protocolos de comunicação intra-veiculares

Considerar os efeitos de falhas e interferências que afetam as redes intra-veiculares desde o projeto dos seus sistemas de controle tornou-se fundamental, pois, a complexidade da eletrônica embarcada, o aumento do fluxo de informação e também as possibilidades de ataques maliciosos, tornaram o projeto destes sistemas uma tarefa cada vez mais complexa. Neste contexto, a presente tese visa explorar formas de integrar e modelar os efeitos de degradação causados por diferentes tipos de falhas que afetam os protocolos de comunicação, na interconexão das unidades de controle eletrônicas (ECUs). Dentre estas falhas, a pesquisa destaca o estudo aprofundado dos transientes elétricos rápidos – EFT, que degradam o desempenho e geram efeitos como perda de pacotes e atrasos de comunicação. Desta forma, contribui-se com uma metodologia para o tratamento de falhas em sistemas críticos de tempo real, desde as fases iniciais do projeto, utilizando a modelagem orientada a aspectos para modelar e especificar requisitos do sistema, de acordo com características transversais dos requisitos não funcionais relacionados a falhas. Para a definição dos requisitos não funcionais, esta pesquisa usa como base o framework RTFRIDA (Real-Time From Requirements to Design using Aspects), o qual foi estendido para agregar com mais detalhes a modelagem de falhas. Para fins de validação da metodologia foi desenvolvido um mecanismo de diagnóstico de degradação de desempenho, o qual foi integrado a um sistema de controle de suspensão ativa. O estudo foi avaliado em diferentes cenários de carga da rede e com injeções de falhas usando dois tipos de hardwares que seguem normas de teste usadas na indústria. Os resultados evidenciaram a aplicabilidade da metodologia, com a modelagem de um mecanismo de diagnóstico que detectou e registrou os distúrbios de desempenho nos cenários estudados. As análises enfatizam a degradação de desempenho acentuada registrada com as injeções EFT de maior amplitude de tensão e menor tempo de rajada, com carga de ocupação da rede acima de 30%. Os experimentos avaliaram o desempenho dos atuais protocolos de comunicação, com melhores resultados obtidos em FlexRay e CAN-FD, o que confirma a evolução dos protocolos para atender as recentes demandas de desempenho da indústria automotiva.Embedded computing applications are increasingly demanding performance and reliability because these factors are critical to the safety of real-time systems. Reliability aspects in design phases is a fundamental point of many researches because with the increase of embedded electronics, network data transmission and also possibilities of attacks on them, make the design of these systems an increasingly complex task. The present thesis aims to explore and correlate different fault types that degrade vehicular communication protocols performance used to interconnect embedded control units (ECUs). Among these faults, the electrical fast transients - EFT are highlighted, since they generate effects such as packet loss and communication delays. Thus, a methodology based on aspect-oriented modeling concepts, in real-time critical systems is proposed, to model and specify system requirements according to cross-cutting concerns of non-functional requirements related to faults. For non-functional requirements specification, this work is based on RT-FRIDA (Real-Time From Requirements to Design using Aspects) framework, which was be extended for fault modeling. Thus, the novel methodology allows fault modeling following the aspect-oriented principles from the early design phases. For the methodology validation purposes, a performance degradation diagnostic mechanism was developed, which was integrated into an active suspension control system. The study was evaluated in different network busload scenarios and with fault injections using two hardware types, certified by standards used in the automotive industry. The results present that the developed mechanism detected performance disturbances, recording occurrence data in the studied scenarios. The analyzes emphasize the best performance degradation observed with EFT injection of higher voltage amplitude, shorter burst time, and busload above 30%. The experiments evaluated the performance of current communication protocols, with better results obtained in FlexRay and CAN-FD, which confirms the protocol’s evolution to meet the recent performance demands of the automotive industry