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Technical Paper
2014-09-16
Ephraim Suhir, Alain Bensoussan
The attributes of and challenges in the recently suggested probabilistic design for reliability (PDfR) concept, and the role of its major constituents - failure oriented accelerated testing (FOAT) and physically meaningful predictive modeling (PM) - are addressed, advanced and discussed. The emphasis is on the application of the powerful and flexible Boltzmann-Arrhenius-Zhurkov (BAZ) model, and particularly on its multi-parametric aspect. The model can be effectively used to analyze and design optoelectronic (OE) devices and systems with the predicted, quantified, assured, and, if appropriate and cost-effective, even maintained probability of failure in the field. The numerical example is carried out for an OE system subjected to the combined action of the ionizing radiation and elevated voltage as the major stimuli (stressors). The measured leakage current is used as a suitable characteristic of the degree of degradation. It is concluded that the suggested methodology can be accepted as an effective means for the evaluation of the operational reliability of the aerospace electronics and OE systems and that the next generation of qualification testing (QT) specifications and best practices for such systems could be viewed and conducted as a “quasi-FOAT,” a sort of an “initial stage of FOAT” that adequately replicates the initial non-destructive segment of the previously conducted comprehensive “full-scale” FOAT.
Technical Paper
2014-09-16
Ralf D. Pechstedt
Recently, there has been an increasing interest in Fiber Optic Sensors (FOS) for aircraft applications. Drivers are general advantages that FOS offer, but that are particularly relevant to aircraft, including weight savings by replacing electrical cables with optical cables, passive and therefore intrinsically safe sensor heads, immunity to Electromagnetic Interference (EMI) and the ability to carry out measurements in harsh environment. The desire to move towards More Electric Aircraft (MEA) or All Electrical Aircraft (AEA) could require the deployment of additional sensors, making weight saving even more important. Further, new opportunities arise in the areas of Structural Health Monitoring (SHM) due to the ease of multiplexing employing Fiber Bragg Gratings (FBG) and the potential to combine operational load monitoring with impact damage detection. Many of the FOS are based on different transducer mechanisms, and hence, have to employ sensor-specific readout systems. However, for ease of maintenance and cost saving purposes, a 'universal interrogator' that can be used with at least a large sub-group of sensors is the preferred option for deployment in aircraft.
Technical Paper
2014-09-16
Mario Luca Fravolini, Matthew Rhudy, Srikanth Gururajan, Silvia Cascianelli, Marcello Napolitano
A measurement device that is extremely important for Unmanned Aerial Vehicle (UAV) guidance and control purposes is the airspeed sensor. As the parameters of feedback control laws are conventionally scheduled as a function of airspeed, an incorrect reading (e.g. due to a sensor fault) of the Pitot tube could induce an incorrect feedback control action, potentially leading to the loss of control of the UAV. In this paper, building on prior research, the authors compare two models for Pitot tube free airspeed estimation. The analysis was carried out based on multiple flight records is acquired from the West Virginia University YF-22 scale model in order to assess their performance. The objective of this study is to establish the accuracy and reliability of the two airspeed estimation techniques for eventual use as the basis for real-time fault detection of anomalies occurring on the Pitot tube sensor. The first technique is based on an Extended Kalman Filter (EKF) that utilizes the nonlinear kinematic relations between GPS, Inertial Measurement Unit and Air Data System signals.
Technical Paper
2014-09-16
Gregory J. Moore, Frank Puglia, Lawrence Myron, Stephen Lasher, Bob Doane, Joe Gnanaraj, Seth Cohen, Arthur Dobley, Ryan Lawrence, Rong Yan
For 70 years Yardney has been a leader in specialty battery and energy systems for military, space, avionics, weapon systems and undersea vehicles. Yardney has evolved since beginning in 1944 in New York City, to Pawcatuck, CT, and since 2013 resides in East Greenwich, RI. The chemistries provided in this time include silver-zinc, magnesium silver chloride, lithium thionyl-chloride, nickel zinc, lithium-ion (Li-ion) and several metal-air technologies. Yardney has made cells from 50 mAh for human implantables to 1000 Ah for submersible vehicles. In addition to battery systems, Yardney also pursues hybrid systems for ground, space, undersea and avionic applications. The beauty of hybrid systems, combining energy sources such as batteries, capacitors, fuel cells and solar, is that they can be used to optimize energy and power density, and with proper design lead to longevity of components and an overall cost savings. Where fuel cells can provide the most energy of these specified constituents on a large scale, at a smaller scale they come at a cost due to their inefficiencies and their bulk.
Technical Paper
2014-09-16
Evgeni Ganev, William Warr, Keming Chen
The more electric architecture (MEA) initiatives continue to be dominating trends in the aerospace industry, as they have for the last two decades. The commercial aircraft business is moving toward no-bleed air environmental control systems (ECS), variable-frequency (VF) and direct current (DC) power distribution buses, and electrical actuation. A typical example is the Boeing 787 platform. The next-generation Boeing and Airbus narrow-body airplanes will most likely use MEA. Some military aircraft already utilize MEA for both primary and secondary flight controls. Substantial progress has recently been made in replacing hydraulic and pneumatic systems with electric ones. These new aerospace and military trends have significantly increased electrical power-generation needs. The overall result has been a significant increase in the challenges to accommodate electrical equipment to the new platforms. This has led to increased operating voltages, and efforts to reduce system losses, weight, and volume.
Technical Paper
2014-09-16
Thierry Cornilleau, Pierre Linard, Paul Moxon, Christopher Nicholas
UK and French Aerospace industries are currently collaborating, under the Anglo-French Government Memorandum of Understanding, on a programme, named ECOA (European Component Oriented Architecture) which aims to reduce the development and through-life-costs of the increasingly complex software systems within military air platforms. The ECOA programme defines an open real-time software architecture, agreed between the programme partners, that meets these goals. The software architecture is based around a number of key concepts: the use of flexible architectural paradigms which provide event and data distribution, the precise specification of software artefacts, allowing a detailed understanding of functional and non-functional behaviour, a better model of distributed real-time behaviour, the support for Model-Driven Engineering (MDE) and automated code generation to reduce development costs, the ability to support any underlying hardware and software platform ensuring the approach is able to support legacy and new build platforms, and the creation of a market for software artefacts, based on an agreed breakdown of mission systems functionality.
Technical Paper
2014-09-16
Puvan Arumugam, Chris Gerada, Serhiy Bozhko, He Zhang, Weeramundage Fernando, Antonino La Rocca, Stephen Pickering
Aircraft platforms are presently being increasingly modernized due to the global effort towards having a more environmentally responsible transport network. Future aircraft platforms are expected to be more fuel efficient and also simpler to service and maintain. The way towards this goal has been identified as a move towards “more electric” systems by replacement of hydraulic and pneumatic sources of power with electrical counterparts. This can lead to an increased reliance on electrical power for a range of primary functions including actuation, de-icing, cabin air-conditioning and engine start. A more electric power generation system plays a key role in this technology and this paper focuses on the design of a starter/generator for such systems. One of the challenges often encountered in the design of a starter/generator for aero-engines is the need to satisfy the two fundamental functions, namely to energize the engines during start-up and to generate power during normal engine operation.
Technical Paper
2014-09-16
Richard Mourn
The AS-1 Aircraft Systems and Systems Integration Committee is updating AS5643 and related standards and recommendations to accommodate both new develops and lessons learned from programs such as the F-35 Joint Strike Fighter and X-47B UCAS. This paper provides insight into how programs like the F-35, which implements more than 60 AS5643/IEEE-1394 devices per plane, utilize AS5643/IEEE-1394 for a vehicle system network. This unprecedented use of a high speed (491.52Mb/s) serial interface on an aircraft proves the capability of AS5643/1394, and opens the door for higher bandwidth communication between the Control Computer and LRUs. While I/O bandwidth is important, system level deterministic behavior is required for most vehicle system networks and AS5643 coupled with 1394 provides the required deterministic behavior. The paper then explains how 1394’s asynchronous stream capability is used by AS5643 to create a programmable rate-based (time-sliced) protocol that meets the rigorous requirements of advanced aerospace and defense system design all while using COTS silicon.
Technical Paper
2014-09-16
Aurelie Beaugency, Marc Gatti, Didier Regis
Since 2000, avionics is facing several changes, mostly driven by technological improvements in the electronics industry and innovation requirements from aircraft manufacturers. First, it has progressively lost its technological leadership over innovation processes in the economy. Second, the explosion of the electronics consumer industry has contributed to shorten even more its technology life cycles, and promoted the use of COTS. Third, the increasing complexities of avionics systems, which integrate more and more functions, have encouraged new players to enter the market. In this context, firms’ ability to quickly face technological changes provides competitive advantage. The aim of this article is to analyze how technological changes can affect the competitive environment of avionics firms. More precisely, we refer to criticality levels as a determinant of the market competitiveness. According to its criticality, each avionic system is ranked from A (highly critical) to E in the DO 178b standard.
Technical Paper
2014-09-16
Evan Racine, Zachary Lammers, Street Barnett, John Murphy, Quinn Leland
Electromechanical Actuation System (EMAS) faces some major technological challenges before it could be fully adopted for primary flight control of aircraft, replacing conventional hydraulic actuation system. One of the challenges is the thermal management of EMAS. The working fluid in conventional hydraulic actuation system acts as a coolant while EMAS does not have a readily available heat sink. Another technical challenge facing EMAS for primary flight control is its highly dynamic demand on aircraft electric power system. Its high peak power demand and regenerative power pose a challenge to aircraft electric power generation and distribution system. The purpose of this study is to analyze EMAS’ transient and dynamic electrical and thermal energy flow under a simulated flight envelope and thermal environment. A laboratory test apparatus was set up to evaluate and characterize the energy flow of an EMA subjected to a simulated dynamic flight control surface load and thermal environment.
Technical Paper
2014-09-16
Hitoshi Oyori, Shingo Nakagawa, Hidefumi Saito, Norio Takahashi, Manabu Seta, Noriko Morioka
With the growth of onboard electrification and the constant improvement of ECO standards, aircraft electricity load has maintained a rapid, high growth. The More Electric Architecture for Aircraft and Propulsion (MEAAP) is emerging as a viable solution for improved performance and eco-friendly aircraft operations. This study proposes a conceptual system design of All Electric Aircraft, or AEA, incorporated with electrical management for onboard systems. The authors have discussed the future of aviation with an airliner. The airliner imagines the likelihood of some effective improvements in aviation by More Electric Aircraft concept. The operators, the pilots and the maintenance crews expect improvement of operability, maintainability and fuel saving, while requiring high reliability and safety. System designers struggle to optimize lighter weight, shorter propulsion operating and lower cost as well as these requests. This study proposes three points for optimization of onboard systems, which are environment control system, flight control system, engine control system, landing gear system and electric power system.
Technical Paper
2014-09-16
Kazuki Shibata, Tomo Maedomari, Kenichi Rinoie, Noriko Morioka, Hitoshi Oyori
In aircraft conceptual design, we consider several different configurations and systems so that performance requirement can be satisfied. When choosing many sets of parameters, designers try to make all the objective functions as good as possible, and then determine the best aircraft configuration. In this case, however, the feasibility of this best aircraft configuration is somewhat doubtful because we haven’t considered aircraft secondary power systems which are indispensable for aircraft operation. Therefore we need to include the consideration of aircraft secondary power systems into the conceptual design. Past studies of conceptual designs with aircraft secondary power systems are few compared with those into which detailed analyses of aerodynamics, structural dynamics, flight stability and propulsion have been integrated. One reason might be that detailed data of existing aircraft is difficult to obtain. Second, basic methods which integrate secondary power systems analyses into conceptual design process haven’t been discussed in detail in the literature.
Technical Paper
2014-09-16
Javier Gazzarri, Nishant Shrivastava, Robyn Jackey, Craig Borghesani
Battery management system design is a complex problem that requires sophisticated models of the battery cell that mimic their electrochemical behavior under a variety of operating conditions. Equivalent circuits offer an adequate balance between fidelity and simulation speed, their parameters reflect direct experimental observations, and they are largely scalable. Scalability is particularly important at the real time simulation stage, where a model of the battery pack runs on a real time simulator that is physically connected to the peripheral hardware in charge of monitoring and control. With modern battery systems comprising hundreds of cells, it is important to count on a modeling and simulation approach that is capable of handling numerous simultaneous instances of the basic unit cell and still be real time capable. In previous publications we presented a technique for the creation of a battery cell model that contains the electrochemical fingerprints of a battery cell based on equivalent circuit model fitting to experimental data.
Book
2014-09-04
William C. Messner
Over the years, the DARPA Challenges in the United States have galvanized interest in autonomous cars, making them a real possibility in the mind of the public, but autonomous and unmanned vehicles have been increasingly employed in many roles on land, in the water, and in the air. Military applications have received a great deal of attention, with weaponized unmanned aircraft (drones) being the most prominent. However, unmanned vehicles with varying degrees of autonomy already have many civilian applications. Some of these are quite familiar (such as the Roomba autonomous vacuum cleaner), while others remain largely out of the public eye (such as autonomous farm equipment). Additional applications and more capable vehicles are rapidly coming to the markets in the years ahead. This book examines a number of economically important areas in which unmanned and autonomous vehicles, also understood here as autonomous technologies, are already used or soon will be. Co-published by SAE International and AUVSI, Autonomous Technologies: Applications That Matter will assist the reader in identifying profitable opportunities and avoiding costly misconceptions with respect to civilian applications of autonomous vehicle technologies as it brings together chapters on how air, water, and ground vehicles are becoming ever more used and appreciated.
Technical Paper
2014-09-01
Zachary A. Collier, Steve Walters, Dan DiMase, Jeffrey M. Keisler, Igor Linkov
Counterfeit electronic components entering into critical infrastructure and applications through the global supply chain threaten the economy and national security. In response to the growing threat from counterfeits, the Society of Automotive Engineers G-19 Committee is developing AS6171. This aerospace standard is focused on testing facilities with a goal of standardizing the process of counterfeit detection. An integral part of the standard is a semi-quantitative risk assessment method. This method assigns risk scores to electronic components based on a number of relevant criteria, and places the components into one of five risk tier levels corresponding to an appropriate level of laboratory testing to ensure the authenticity of the component. In this way, the methodology aims at standardizing the risk assessment process and bases the identified risk as guidance for commensurate testing protocols. This paper outlines the risk assessment method contained within AS6171 and briefly explores other complementary efforts and research gaps within the G-19 and electronics community.
Article
2014-08-20
Sensors have become central elements in powertrains as designers add functions from stop-start to double clutches. More stringent fuel efficiency and emissions requirements are driving many changes in sensor technologies as well as in cabling and standards.
Standard
2014-08-20
This SAE Aerospace Information Report (AIR) defines the areas where incompatibility may exist between the selected wire and the electrical connector in which it is terminated and how to design for compatibility. Refer to ARP914 for a glossary of connection terms.
Article
2014-08-19
A former player on Google's self-driving car project has been named head of a new Continental unit that will focus on intelligent transportation systems (ITS). Based in Silicon Valley, Seval Oz will lead an international team to be composed of engineers and related professionals from the information-technology and automotive industries.
Article
2014-08-19
The U.S. NHTSA (National Highway Traffic Safety Administration) is seeking information and insights from automotive and related industries as it moves to mandate certain vehicle-to-vehicle (V2V) technologies for improved safety.
Standard
2014-08-19
This SAE Recommended Practice identifies graphic symbols used in electrical circuit diagrams. The symbols aid troubleshooting electrical systems.
Article
2014-08-18
Volvo Bus and Swiss technology group ABB are collaborating to develop and commercialize hybrid- and full-electric buses that employ “open standards-based” dc fast-charging systems. Buses will be charged quickly through an automatic roof-top connection system at bus stops, or through cabled charging systems overnight.
WIP Standard
2014-08-18
This SAE Standard is intended to be used as a guide for manufacturers and users of general purpose industrial machines to provide a reasonable degree of protection for personnel during normal operation and servicing. This document excludes skid steers which are covered by SAE J1388. Avoidance of accidents also depends upon the care exercised by such persons (see SAE J153). Inclusion of this standard instate, federal, or any laws or regulations where flexibility of revision is lacking is discouraged.
Article
2014-08-15
Fox Electronics offers two popular crystal lines as standard stock in the extended temperature range of -40 to +85°C, with a total of five packages and 14 different frequencies.
Article
2014-08-15
Edmund Optics’ TECHSPEC Germanium meniscus lenses feature a durable design that is ideal for use in a variety of demanding IR applications, including IR imaging or surveillance, remote sensing, and IR spectroscopy.
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