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A Systematic Approach to Development Assurance and Safety of Unmanned Aerial Systems

Textron Aviation-Cory R. Laflin
  • Technical Paper
  • 2020-01-0043
To be published on 2020-03-10 by SAE International in United States
The unrestrained design space for unmanned aerial systems (UAS) presents challenges to accurate safety assessment and the assurance of development to appropriate levels of rigor within those systems. The established safety and development assurance standards and practices were developed for vehicles operating in highly controlled conditions with continuous oversight. The very nature of unmanned systems introduce new failure conditions, even in those systems operating within the strict rules of the National Airspace System (NAS), particularly failures of control and command, situational awareness, and control security. Beyond those, the new concepts of operation being conceived by UAS developers introduce their own new set of considerations with regards to operating in uncontrolled airspace, often in close proximity to bystanders. These new concepts require new technologies beyond those currently supported by the hardware and software development assurance processes. However, the established standards and practices of aircraft development assurance and safety assessment can be adapted for the broader world of UAS applications, provided that the considerations driven by the new concepts of operation can be identified and properly analyzed.…
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An Approach to Verification of Interference Concerns for Multicore Systems (CAST-32A)

Rapita Systems, Inc., Ltd.-Steven H. VanderLeest, Christos Evripidou
  • Technical Paper
  • 2020-01-0016
To be published on 2020-03-10 by SAE International in United States
The avionics industry is moving towards the use of multicore systems to meet the demands of modern avionics applications. In multicore systems, interference can affect execution timing behavior, including worst case execution time (WCET), as identified in the FAA CAST-32A position paper. Examining and verifying the effects of interference is critical in the production of safety-critical avionics software for multicore architectures. Multicore processor hardware along with aerospace RTOS providers increasingly offers robust partitioning technologies to help developers mitigate the effects of interference. These technologies enable the partitioning of cores for different applications at different criticalities and make it possible to run multiple applications on one specific core. When incorporated into system-design considerations, these partitioning mechanisms can be used to reduce the effects of interference on software performance. In this paper we describe a novel approach to verifying the effectiveness of RTOS interference mitigation on the final hosted software. We showcase the use of the proposed approach on the NXP T2080 multicore board. The approach follows a V-model based methodology in which high- and low-level requirements…
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A MATLAB Simulink Based Co-Simulation Approach for Vehicle Systems Model Integration

Army Corps Of Engineers-Mark Bodie
PC Krause & Associates-Brian C. Raczkowski, Nicholas Jones, Tim Deppen, Charles Lucas, Rodney Yeu, Eric Walters
  • Technical Paper
  • 2020-01-0005
To be published on 2020-03-10 by SAE International in United States
In this paper, a MATLAB-Simulink based general co-simulation approach is presented which supports multi-resolution simulation of distributed models in an integrated architecture. This approach was applied to simulating aircraft thermal performance in our Vehicle Systems Model Integration (VSMI) framework. A representative advanced aircraft thermal management system consisting of an engine, engine fuel thermal management system, aircraft fuel thermal management system and a power and thermal management system was used to evaluate the advantages and tradeoffs in using a co-simulation approach to system integration modeling. For a system constituting of multiple interacting sub-systems, an integrated model architecture can rapidly, and cost effectively address technology insertions and system evaluations. Utilizing standalone sub-system models with table-based boundary conditions often fails to effectively capture dynamic subsystem interactions that occurs in an integrated system. Additionally, any control adjustments, model changes or technology insertions that are applied to any one of the connecting subsystems requires iterative updates to the boundary conditions. When evaluating a large set of trade studies, the number of boundary condition models and time to generate these models…
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New Architectural Design of the Runtime Server for Remote Vehicle Communication Services

SAE International Journal of Connected and Automated Vehicles

Germany-Vladivy Poaka
Technische Universität Clausthal, Germany-Sven Hartmann
  • Journal Article
  • 12-03-01-0002
Published 2020-01-17 by SAE International in United States
This article addresses the issue of a design to provide remote vehicle communication services sustainably. These services include new features such as remote repair of Electronic Control Unit (ECU)’s software errors and feature on demand, to mention just a few key objectives. With the usual implementations of the Modular Vehicle Communication Interface (MVCI) runtime server [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14] many difficulties remain [15]. They are not sustainable and require dedicated hardware. The Dictionary Server discussed here provides necessary data to diagnostic applications in general, without putting at risk Original Equipment Manufacturer (OEM)’s expertise. It also provides data to the road infrastructure for V2V- and Vehicle-to-Infrastructure (V2X)-based services. This crucial diagnostic data contains ECUs’ communication parameters, memory programming data, and other available functions. They are kept confidentially by OEMs. Furthermore, our solution is nondisruptive, as it also supports traditional vehicle communication services. We evaluated a prototype in terms of time complexity, scalability, and availability.
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Brake System Thermal Performance for Brazil Market Battery Electric Vehicles

General Motors, LLC-David Antanaitis
  • Technical Paper
  • 2019-36-0019
Published 2020-01-13 by SAE International in United States
The discussion in the braking industry that has been ongoing for over a decade now on how to specify brake systems for regenerative-brake intensive vehicle applications has intensified considerably in the past few years as the automotive industry ponders a future where electric vehicles become predominant. Major automotive manufactures have announced plans to create dedicated electric-only vehicle architectures, from which to offer a full range of electric vehicle configurations. The time to really figure out the translation of Voice of the Electric Vehicle Customer to technical requirements and brake system content is approaching very rapidly. One of the major design decisions in the brake system is the sizing of foundation brake components for thermal performance. There is no question that regenerative brakes can significantly reduce the demand on the friction brakes in normal usage, sometimes by a full order of magnitude or more. Brakes no longer need to be sized for everyday use, rather, the sizing is driven by “limit cases” such as failure of the regen system, a full state of charge in the…
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Powertrain Hardware In The Loop X Vehicle Hardware In the Loop: How to Optimize Their Use During the Software Development Cycle

FCA - Fiat Chrysler Automotive-Jeeves Lopes dos Santos, Elaine Cristina Guglielmoni Silva, Cleber Albert Moreira Marques, Gustavo Maximo Urquiza de Sá, José Henrique Silva, Mauricio Vianna de Resende
  • Technical Paper
  • 2019-36-0311
Published 2020-01-13 by SAE International in United States
The advance of technology and the demand for new features on vehicles has been challenging the automotive industry to find ways to speed up its development process, while increases the robustness and quality of its products. On this context, the embedded software development for vehicles has been directly impacted. In other words, the number of Electronic Control Units (ECUs) considerably increased on the past few years and the number of lines of code, as well as their complexity, have been exponentially increased. In order to deal with this new reality, besides the automotive test prototypes used during the development, the automotive industry has been using different virtual environment to develop, verify and validate its products. As an example, we can see an increase in the use of different Hardware In The Loop system architectures (HILs) such as Powertrain HIL (with real Engine and Transmission Control Modules - ECM and TCM) and Vehicle HILs (with real ECM, TCM, several other ECUs, and also several electronic components that composes the vehicle). Each of these options has its…
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Unsettled Domains Concerning Autonomous System Validation and Verification Processes

EllectroCrafts Aerospace-Fabio Alonso da Silva
  • Research Report
  • EPR2019012
Published 2019-12-30 by SAE International in United States
The Federal Aviation Administration (FAA) and the Department of Transportation’s (DOT’s) National Highway Traffic Safety Administration (NHTSA) face similar challenges regarding the regulation of autonomous systems powered by artificial intelligence (AI) algorithms that replace the human factor in the decision-making process. Validation and verification (V&V) processes contribute to implementation of correct system requirements and the development life cycle - starting with the definition of regulatory, marketing, operational, performance, and safety requirements. The V&V process is one of the steps of a development life cycle starting with the definition of regulatory, marketing, operational, performance, and safety requirements. They define what a product is, and they flow down into lower level requirements defining control architectures, hardware, and software. The industry is attempting to define regulatory requirements and a framework to gain safety clearance of such products. This report suggests a regulatory text and a safety and V&V approach from an aerospace engineering perspective assessing the replacement of the human driver from the decision-making role by a computational system. It also suggests an approach where aerospace guidelines can…
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Kirigami Inspires New Method for Wearable Sensors

  • Magazine Article
  • TBMG-35627
Published 2019-12-01 by Tech Briefs Media Group in United States

Researchers have applied kirigami architectures to graphene, an ultra-thin material, to create sensors suitable for wearable devices. Simulations were done using online software on a nanomanufacturing node, the first of its kind to be developed.

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Next Generation Power Distribution Unit in Wiring Harness

Mahindra & Mahindra, Ltd.-Boobala Krishnan D, Himanshi Dua, T Vijayan, Apurbo Kirty
  • Technical Paper
  • 2019-28-2571
Published 2019-11-21 by SAE International in United States
With the exponential advancement in technological features of automobile’s EE architecture, designing of power distribution unit becomes complex and challenging. Due to the increase in the number of features, the overall weight of power distribution unit increases and thereby affecting the overall system cost and fuel economy. The scope of this document is to scale down the weight and space of the power distribution unit without compromising with the current performance.The concept of next generation power distribution unit in automobiles is achieved using miniaturization of its sub-components which involves replacing the mini fuses and JCASE fuses with LP mini and LP JCASE fuses respectively. The transition doesn’t involve any tooling modification and hence saves the tooling cost. Furthermore, to address stringent weight and space targets, LP mini fuses and LP JCASE fuses were further replaced with micro-2 fuse and M-case fuse respectively. Similarly, Micro relay and Mini relay were replaced with Ultra micro and high current micro relay respectively.We took MPV segment vehicle for our initial testing and validation and it has been observed to…
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Design and Development of Automotive Battery Management System

Assistant Professor, COE, Pune-Meera Murali
Associate Professor, COE, Pune-D.N. Sonawane
  • Technical Paper
  • 2019-28-2498
Published 2019-11-21 by SAE International in United States
Battery operated vehicle needs accurate management system because of its quick changes in State of Charge (SoC) due to aggressive acceleration profiles and regenerative braking. Li-ion battery needs control over its operating area for the safe working. The main objective of the proposed system is to develop a BMS having algorithms to estimate accurate SoC, balance individual cells, thermal management, and provide safe area of operation defined by voltage and temperature. Proposed methodology uses Coulomb Counting as well as Model-based Design approach wherein nonlinear behavior of battery is modeled as Equivalent Circuit Model to compute the SoC and degradation effect on battery to decide the end of life of battery. Also performing Inductive Active Balancing on cells to equalize the charge. The study aims on deploying the model-based system on embedded platform which would help industry to reduce the model development time and focus on development of controlling algorithms for high end users. Active Balancing Architecture proposed here reduces the complexity of algorithm and at the same time decreases the balancing time.
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