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Viewing 31 to 60 of 21999
2015-09-15
Technical Paper
2015-01-2479
Stefan Benischke, Frank Thielecke
Future high lift system configurations without mechanical interconnection of the flaps would allow for novel functionalities. Through a differential setting of the individual flap surfaces, an optimization of aerodynamic performance can be achieved. Single flap drive systems are possible solutions to implement this kind of multifunctional high lift systems. The previously mechanical coupling needs to be replaced by approved equivalent means. This directly results in high demands on control and monitoring of the multiple single drive systems in order to preserve a safe operation. Control strategies for a new concept of a multifunctional high lift system are presented in this paper. The presented concept comprises four single flap surfaces, each driven by a local transmission system powered by a local power control unit. This architecture requires an innovative control strategy for a safe operation of a single drive system as well as synchronous movement of multiple systems.
2015-09-15
Technical Paper
2015-01-2481
Rudolf Neydorf
Synthesis of Time Quasi-Optimal Asymptotically Stable Control Laws Rudolf Neydorf The solution of the both synthesis and implementation problems of high-rapid rates control laws is extremely important for the development of automatic control systems of the aircraft. This is due to the high speed of such vehicles. Along with this, it is imperative that control laws provide that system is asymptotically stable, as the basis for the reliability of their controlled motion. Another important objective of the method of synthesis of control laws for aircraft is compulsory compliance with strict limitations on the values of control inputs at the actuation devices. It is equally important that the control laws provides limitations on the state variables of aircraft, such as velocity, acceleration, etc. Pontryagin's maximum principle is aimed at solving such a time-optimal problem with the limited command variable.
2015-09-15
Technical Paper
2015-01-2478
Tobias Kreitz, Riko Bornholdt, Matthias Krings, Karsten Henning, Frank Thielecke
The paradigm shift to focus on an enhancement of existing aircraft systems raises the question which of the many possible incremental improvements results in an advantageous solution still considering all existing requirements. Hence, new methodologies for aircraft system design are a prerequisite to cope with such huge and complex design spaces. In the case of flight control system optimization, major design variables are the control surface configuration and actuation, as well as their functional allocation. Possible architecture topologies have to be verified i.a. with respect to system safety requirements. In this context, flight dynamic characteristics and handling qualities of the fully operational as well as several degraded system states of each topology have to be evaluated and checked against common specifications. Here, a model-based verification of the requirements is favorable, resulting in a rapid reduction of the design space.
2015-09-15
Technical Paper
2015-01-2409
Constanza Ahumada S., Seamus Garvey, Tao Yang, Patrick Wheeler, Herve Morvan
This paper considers the electromechanical interconnection between the electrical power system of the More Electric Aircraft (MEA) and the shaft connecting the engine to the generator. In order to probe the existing coupling between these two systems and therefore the necessity of studying them together, the effect of an electric load impact on the mechanical system of the MEA will be analyzed. As the MEA concept, replaces the pneumatic, hydraulic and mechanical systems by electrical systems, the electrical power rating of the MEA is considerable higher than the power rating of existing aircraft and consequently new challenges arise. A larger electrical power system implies larger generators and higher power loads, which can have higher associated electrical transients. Moreover, unlike in previous aircraft and most ground based electrical power systems, in the MEA the short term changes in power tend not to be small compared to the total load in the system.
2015-09-15
Technical Paper
2015-01-2458
Giuseppe Sirigu, Manuela Battipede, Piero Gili, Mario Cassaro
The revolution of the air traffic system, started with the introduction of the 4-Dimentional Trajectories (4DTs), imposes the development of new class of Flight Management Systems (FMS), capable of solving a constrained non-linear optimization problem to provide the aircraft with real time reference flight parameters, necessary to fly the aircraft through a predefined sequence of waypoints, while minimizing fuel consumption, noise and pollution emissions. The main goal is to guarantee safety operations through the aircraft separation and sequencing while reducing the aircraft environmental impact, according to the international research programs like SESAR, Clean Sky and NextGen. The actual challenge is to meet these requirements with minimum modifications of the avionic systems. This goal is achieved by developing a FMS that uses the existing aircraft autopilot suite in order to follow the calculated reference trajectory.
2015-09-15
Technical Paper
2015-01-2439
Martin Hunter
It is generally accepted that the development of hardware and software for safety critical systems follow their own lifecycles as defined by standards such as RTCA DO254 and RTCA DO178C. What is less clear, is what should be done to ensure the system safety objectives are met when the software is installed in the electronic hardware. This paper seeks to discuss the activities that may be undertaken do demonstrate not only that the integration of the software and hardware "work" together, but they do so in a manner that meets the safety objectives in line with the guidance in SAE ARP4754A. According to ARP 4754A, hardware and software are different “items” developed according to their own requirements and standards, when two or more items are brought together, they are a system, which may be part of a larger system. Therefore system level considerations need to be applied from the beginning of the development program addressing the system safety and certification activities.
2015-09-15
Technical Paper
2015-01-2520
Thabet Kacem, Jeronymo Carvalho, Duminda Wijesekera, Paulo Costa, Márcio Monteiro, Alexandre Barreto
Since its emergence, Automatic Dependent Surveillance Broadcast (ADS-B) has been considered as a major contribution to air traffic control (ATC) surveillance. However, despite the several benefits that this promising technology has to offer, it suffers from a major security flaw since ADS-B packets are sent in clear text without enforcing any kind of security property. In this paper, we enhance a security framework, which we describe in a previous paper, aiming at detecting and mitigating attacks targeting ADS-B protocol, with a cognitive engine. First, this would facilitate the physical risk assessment of the ADS-B attacks based on the collected data describing the aircraft and its surrounding. Second, it would be beneficial to the ATC controllers who would have a better idea about the best ways to optimize the aircraft taking off and touching down without any disruptions from possible attacks targeting this technology.
2015-09-15
Technical Paper
2015-01-2438
Robert E. Voros
Aerospace Recommended Practice 4754 Revision A (ARP4754A), “Guidelines for Development of Civil Aircraft and Systems,” and ARP4761, “Guidelines and Methods for Conducting the Safety Assessment Process on Civil Airborne Systems and Equipment,” together describe a complex set of intertwining processes which comprehensively prioritize development activities for a product’s systems based on their safety criticality. These processes work at specific levels of detail (aircraft and system) and interact with a set of processes at lower levels of detail (item) defined by Radio Technical Commission for Aeronautics (RTCA) standards. The aircraft and system development process (ARP4754A) supplies functions, requirements, and architectural definitions to the system safety process (ARP4761), which in turn supplies Development Assurance Levels back to the development process and on to the RTCA processes.
2015-09-15
Technical Paper
2015-01-2584
Andrew Dickerson, Ravi Rajamani, Mike Boost, John Jackson
Based on a advanced modeling approach, we are developing a system for estimating the remaining useful life (RUL) for Li-Ion batteries for aerospace applications. We begin with a set of functional requirements that are further translated to detailed system and maintenance specifications. We will show how this RUL calculator will be translated to actual algorithms and operating procedures inside a battery’s management unit. Test data will be used to validate the robustness and goodness in the predictions. We will also share plans for the future along with implications for certification of the system. This is important because batteries are governed by FAA regulations and are dispatch critical for certain applications.
2015-09-15
Technical Paper
2015-01-2528
Srikanth Gururajan
In recent years, there has been an increase in the use of Unmanned Aerial Systems (UAS) in both civilian as well as military sectors for a wide range of applications including aerial reconnaissance of military targets, monitoring traffic, geological mapping, search and rescue among others. Typically with the use of UAS, there is a premium on total weight and cost, in order to maximize their payload potential and as a consequence, the use of redundant sensors is uncommon. In addition, UAS have gained wide acceptance as the platforms of choice for implementing high risk/high reward flight control algorithms, especially addressing sensor and actuator failure scenarios, thanks to the low logistical burden. This research effort describes the design and simulation of a distributed Neural Network (NN) based fault tolerant flight control scheme for sensor and actuator failures and the interface of the scheme within a simulation/visualization environment.
2015-09-15
Technical Paper
2015-01-2472
Tom Owen
SUAV is a 4 year investigation with the aim of designing, manufacturing and integrating a 3kg Solid Oxide Fuel Cell (SOFC) into an existing 10kg fixed wing UAV which is already in commercial service. The project comprises of a collaboration of 1o partners, each having a commercial or scientific interest in the design. Each partner provides specialist knowledge at system component level. This paper will present an overview of the problem space and present the methods used to generate the system level requirements. A top level overview will then be given of the resultant system design. This paper will also discuss some of the platform performance benefits and drawbacks of fuel cell operation.
2015-09-15
Technical Paper
2015-01-2523
Pierre Coustal, Franck Tailliez
In the Integrated Modular Avionics (IMA) domain, THALES developed a high performance communication network named SAEN (Self Adaptive Embedded Network). SAEN is a switchless network solution, fully embedded in a single Network Component Interface (NCI), aimed to easily interconnect several modules of a system, in any mesh network topology. Once each module is equipped with its network component, just connect them together to realize the wanted topology and switch ‘on’ the modules power supplies. A power-on, all the nodes of the network aggregate them to form a whole global and coherent network, managing autonomously its configuration and the optimal static routing between any emitter and receiver. The constituted network is deterministic, autonomous, self-discovery, auto-adaptive to the network variations and guarantees an optimal routing in any situation of the graph, as long as a path exists.
2015-09-15
Technical Paper
2015-01-2525
Dave Duncan
The verification of Robustness is conceptually simple, once the reasonable set of “abnormal operating conditions” has been established. During testing those conditions are created and the FPGA/CEH response is noted. The FPGA/CEH response need not be “to work normally” but should at a minimum return to normal operation once normal conditions are reestablished. Part of the analysis is to establish acceptable FPGA/CEH responses to the “abnormal operating conditions”. Some of the acceptable responses may actually affect the LRU/CCA or Software for the system, thus timely identification will limit risks. The implementation of this testing is treated no differently than any other. The key here is to know the scope of the tests and plan accordingly. The understanding that the test environment will need to be capable of generating these “abnormal operating conditions” is key to properly planning for and establishing the infrastructure needed.
2015-09-15
Technical Paper
2015-01-2536
Rinky Babul Prasad, Vinukonda Siddartha
Recent years have seen a rise in the number of air crashes and on board fatalities. Statistics reveal that human error constitutes upto 56% of these incidents. This can be attributed to the ever growing air traffic and technological advancements in the field of aviation, leading to an increase in the electronic and mechanical controls in the cockpit. Accidents occur when pilots misinterpret gauges, weather conditions, fail to spot mechanical faults or carry out inappropriate actions. Currently, pilots rely on flight manuals (hard copies or an electronic tablet) to respond to an emergency. This is prone to human error or misinterpretation. Also, a considerable amount of time is spent in seeking, reading, interpreting and implementing the corrective action. The proposed head mount assist for the pilot eliminates flight manuals, by virtually guiding the pilot in responding to in-flight necessities.
2015-09-15
Technical Paper
2015-01-2535
Steven Donald Ellersick, Bill Reisenauer, Mickey Jacobson, Newel Stephens
The past twenty years have seen tremendous change in the Avionics display and flight deck lighting due to the application of solid-state LED (light emitting diode) light sources and LCDs (liquid crystal displays). These advances significantly benefit the customer and pilot user when integrated correctly. This paper discusses recommended practice and guidance given in SAE ARP 4103 for modern Avionics flight deck lighting systems to satisfy the end user and obtain certification. SAE ARP 4103 Flight Deck Lighting for Commercial Transport Aircraft has recently been revised to keep up with the state of the art and add clarification where needed. ARP 4103 contains recommended Avionics flight deck lighting design and performance criteria to ensure prompt and accurate readability and visibility, color identification and discrimination of needed information under all expected ambient lighting and electrical power conditions.
2015-09-15
Technical Paper
2015-01-2554
Kevin Landry, Jean-François Boland, Guy Bois
Modern aircrafts must include an increasingly amount of functionalities to satisfy the needs of the customers. Therefore, the communication needs of avionic systems are growing. Furthermore, the portability and reusability of applications are current challenges of the avionic industry. The use of the Data Distribution Service (DDS) middleware technology would reduce the complexity of communications and ease the portability and reusability of applications with its standardised interface. Few previous works used a DDS middleware within the avionic industry and those didn't take into account the impact of this technology on the applications performances. Therefore, this paper presents an impact evaluation of using a DDS middleware on the performances of avionic applications. To do so, an automatic flight control system (AFCS) was modeled with Simulink to control a Boeing 747-400 simulated within the X-Plane flight simulator.
2015-09-15
Technical Paper
2015-01-2524
Srikanth Gampa
Multi core platforms offer high performance at low power and have been deemed as future of size, weight and power constrained applications like avionics safety critical applications. Despite these advantages, multi core platforms (hardware and software) pose significant certification challenges for safety critical applications and hence there has been limited usage in avionics and other safety critical applications. Many multicore platform solutions which can be certified to DO-254 & DO 178B Level A are commercially available. There is a need to evaluate these platforms w.r.t certification requirements before deploying them in the safety critical systems thereby reducing the program risks. This paper discusses the advantages of multi core platforms in terms of performance, power consumption and weight/size.
2015-09-15
Technical Paper
2015-01-2538
Yixiang Lim, Alessandro Gardi, Roberto Sabatini
With the currently foreseen growth of air traffic globally, the effects of aircraft condensation trails (contrails) are predicted to become significant by 2050. Currently, the physics behind the formation of contrails is relatively well understood. However, research regarding the persistence or dissipation timescales of contrails is still ongoing, with particular focus on their evolution into cirrus clouds, since these clouds have been shown to contribute to global warming. Currently, the formation of cirrus is believed to be affected by the microphysics of contrail formation and possibly by wind shear. In the aviation industry, there is an ongoing progress in the development of an integrated flight management/air traffic management system to account for contrail mitigation.
2015-09-15
Technical Paper
2015-01-2434
Tian Lirong, Mu Ming
Abstract: Chinese aviation industry is now making great efforts in developing civil aircraft, as a result, more opportunities for Chinese companies to be involved in these programs, but Chinese companies are lack of experience in this area, certification is one of the challenges for them,so they are expected to be more competitive in design and certification. ACTRI (Aeronautical Computing Technique Research Institute) is a airborne computer supplier in China, to be able to develop electronic equipment for civil aircraft, the company has being working on processes improvement including the system process based on ARP4754 since 2008. This paper describes the customized system process in Chinese context.
2015-09-15
Technical Paper
2015-01-2456
Roberto Sabatini, Terry Moore, Chris Hill
The integration of Global Navigation Satellite System (GNSS) integrity augmentation functionalities in Unmanned Aerial Vehicles (UAV) Detect-and-Avoid (DAA) architectures has the potential to provide an integrity-augmented DAA solution suitable for cooperative and non-cooperative scenarios. In this paper, we evaluate the opportunities offered by this integration, proposing a novel approach that maximizes the synergies between Avionics Based Integrity Augmentation (ABIA) and UAV cooperative/non-cooperative DAA architectures. In the proposed architecture, the risk of collision is evaluated by setting a threshold on the Probability Density Function (PDF) of a Near Mid-Air Collision (NMAC) event over the separation area in both cooperative and non-cooperative cases.
2015-09-15
Technical Paper
2015-01-2522
Mirko Jakovljevic, Jan Radke, Perry Rucker
In this paper, we will describe basic principles for design of open IMA architectures using VPX standard, and describe based on space avionics architetcure, how those components can be used for definition of open VPX-based architectures for IMA and integrated systems. VPX, as a switched fabric, supports the design of advanced integrated systems using technologies such as deterministic Ethernet, which can be used in backplane and backbone applications. In cases where functional interrelationships and Ethernet network bandwidth sharing is deterministic and all logical links among critical function have configurable quality of service with guaranteed timing, the complexity challenges in design of advanced integrated architectures can be much simpler to handle and mitigate. This enables design of truly open and flexible modular embedded systems, which can host hard real-time, real-time, and soft functions at lower system lifecycle costs.
2015-09-15
Technical Paper
2015-01-2531
Lin Bao, Guy Bois, Jean-François Boland, Julien Savard
The Integrated Modular Avionics (IMA) architecture has been a crucial concern for the aerospace industry in developing more complex systems, while seeking to reduce space, weight and power (SWaP), as well as development, certification and production time. From a software perspective, that objective pushes developers to migrate toward a safety critical space and time partitioning environment, usually compliant with the ARINC 653 standard which specifies a series of robust partitioning mechanisms and services that an operating system (OS) must satisfy to guarantee such isolation. The research work presented in this paper aims to propose to the aerospace industry a set of time-effective and cost-effective solutions for the integration and functional validation of IMA systems. The proposed methodology mainly focuses on a novel model-based engineering design flow (MBE). In the first step of the design flow, the modeling language AADL is used to describe the IMA architecture.
2015-09-15
Technical Paper
2015-01-2527
Mirko Jakovljevic, Jan Radke
In this paper we will provide an overview o tools and methods required for design and verification fo complex AFDX/TTEthenret networks. One of key aspects is the toolchain discussion and verification of timing guarantees and configuration.
2015-09-15
Technical Paper
2015-01-2545
Reza Ahmadi, Oliver Marquardt, Marc Riedlinger, Reinhard Reichel
An aircraft’s cabin has to cope with frequent cabin layout rearrangements as well as technical and functional modifications during its operational lifecycle, in order to stay aligned with business demands and technological progress. Additionally the cabin faces extensive customizations during its production, to underline the corporate design of airlines and improve passenger perception. Such changes in the cabin induce major modifications in the cabin management system (CMS).Therefore it is inevitable for CMS to be highly changeable and offer an easy and agile change process. Today’s CMS solutions face this challenge with configurable system architectures. Such architectures normally offer a vast change domain, but also need time consuming and error-prone change processes. The generation of a complete CMS configuration can even last more than 100 days.
2015-09-15
Technical Paper
2015-01-2619
Karl-Otto Strömberg, Stefan Borgenvall, Mohamed Loukil, Bertrand Noharet, Carola Sterner, Magnus Lindblom, Orjan Festin
LWPT (Lightweight Production Technology) is today a well-established technology in the automotive industry. By introducing light weight fixtures manufactured from Carbon Fiber Reinforced Plastics (CFRP), new production processes have been developed in the automotive industry. This has resulted in increased productivity, reduced investment costs and increased flexibility. The next step is to introduce this technology in the aerospace industry. Aircraft components are complex and large products having small tolerance windows. Fixtures manufactured in FRP materials allow integration of health monitoring sensors directly into the structure. This means that information on displacements can be recorded both when the fixture is stationary, while work is being performed, as well as in a pulsed production line when the fixture is moving between the assembly stations.
2015-09-15
Technical Paper
2015-01-2388
Luis Rabelo, Tom Clark
For many critical space operation systems, timely recognition of an anomalous condition immediately starts the evaluation process. For complex systems, isolating the fault to a component or subsystem results in corrective action sooner so that undesired consequences may be minimized. These beneficial anomaly detection and fault isolation capabilities are widely recognized and have resulted in the development of innovative techniques for quickly discovering underlying system problems. This paper will address augmenting a legacy system with additional detector/isolator capabilities best suited for that system. A cryogenic liquid hydrogen (LH2) tank pressurization subsystem (from the Kennedy Space Center (KSC) launch pad) is the basis for the model. This system is operated remotely and supports time-critical and high-risk operations making it a good candidate to supplement with this technology. The proposed approach models the existing system using the System Modeling Language (SysML).
2015-09-15
Technical Paper
2015-01-2403
Jennifer C. Shaw, Steven Fletcher, Patrick Norman, Stuart Galloway, Graeme Burt
A number of concepts have been proposed to meet future aircraft performance goals as championed by NASA. One such aircraft concept under consideration is Turboelectric Distributed Propulsion (TeDP). This features a large number of thrust-producing superconducting motors powered by two superconducting generators placed on each turbofan engine and connected through a DC distribution network. A key aspect in any design concept is the ability to prove that the system will exhibit a satisfactory reliability for all intended operating conditions. To be completed in full, this requires extensive safety and failure analysis from the architectural down to the component level. The purpose of this paper is to support this safety and failure analysis by performing a high level architectural failure analysis of the electrical propulsion network of a TeDP aircraft to help determine how faults and failures may influence its operation.
2015-09-15
Technical Paper
2015-01-2404
Catherine E. Jones, Karen Davies, Patrick Norman, Stuart Galloway, Graeme Burt, Michael Armstrong, Andrew Bollman
Distributed electrical propulsion has been predicted as a possible solution to enable air travel to continue to grow at high levels, whilst meeting noise, emissions and system performance targets. Such aircraft will require a complex electrical power system, to deliver power to propulsor motors from gas turbine driven generators. In order ensure high enough power densities can be reached, it is well documented in the literature that such systems should be superconducting. Hence the development of a suitable power system which is sufficiently light and efficient, in order to be viable for the aerospace application, is challenging due to a number of unanswered questions regarding the best choice of system architecture, suitable levels of redundancy and fault management and protection strategies. Key to the development of the distributed electrical propulsion system is the understanding of how faults propagate in the network, and based on this what possible protection strategies may be.
2015-09-15
Technical Paper
2015-01-2412
Tao Yang, Serhiy Bozhko, Greg Asher
The more-electric aircraft (MEA) is the developing trend for the next generation airplanes. Recent advances in power electronics, electrical drives and modern control techniques make it possible to replace many functions which are conventionally managed by hydraulic, pneumatic and mechanical power, with electrical power driven devices. Such replacement would increase reliability, capability, maintainability, reduced weight and volume, and provide higher survivability in aircraft operations. The use of MEA technology will result in a large number of AC/DC converters supplying power for functions as fuel pumps, cabin pressurization, air conditioning, engine start and flight control. There are two alternative ways to convert the AC power to the DC power: the pulse-width modulation (PWM) active front-ends and passive multi-pulse converters. The former approach seemingly needs considerable development to meet the reliability requirement for aircraft applications.
2015-09-15
Technical Paper
2015-01-2428
Richard Ambroise, Gabriel Godfrey
The smartphone in your pocket, the tablet you use to browse the web, the safety systems in your automobile: they’re all the beneficiaries of fast-evolving computer and electronic component technology. These components are lighter, hold more data, and can perform increasingly complex tasks. This electronic evolution has had an impact in the aviation industry as well. The electronic components used in today’s engines can do more than ever before, but the need to replace older components has introduced some added complexity. Until now. The problem is obsolescence. Driven by an ever-demanding consumer market, electrical components – including those used for aircraft engines – are evolving faster than ever. Engine components installed just a few years ago are no longer being made. This means engine manufacturers need to install new models when replacing those older models or when building new engines.
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