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Viewing 1 to 30 of 106
2014-09-16
Technical Paper
2014-01-2101
Joseph Dygert, Melissa Morris, Patrick Browning
Abstract The high demand for traditional air traffic as well as increased use of unmanned aerial systems (UAS) has resulted in researchers examining alternative technologies which would result in safer, more reliable, and better performing aircraft. Active methods of aerodynamic flow control may be the most promising approach to this problem. Research in the area of aerodynamic control is transitioning from traditional mechanical flow control devices to, among other methods, plasma actuators. Plasma actuators offer an inexpensive and energy efficient method of flow control. Dielectric Barrier Discharge (DBD), one of the most widely studied forms of plasma actuation, employs an electrohydrodynamic (EHD) device which uses dominant electric fields for actuation. Unlike traditional flow control methods, a DBD device operates without moving components or mass injection methods.
2014-09-16
Technical Paper
2014-01-2111
Shweta Sanjeev, Goutham Selvaraj, Patrick Franks, Kaushik Rajashekara
Abstract The transition towards More Electric Aircraft (MEA) architectures has challenges relating to integration of power electronics with the starter generator system for on-engine application. To efficiently operate the power electronics in the hostile engine environment at high switching frequency and for better thermal management, use of silicon carbide (SiC) power devices for a bi-directional power converter is examined. In this paper, development of a 50 kVA bi-directional converter operating at an ambient temperature of about 2000C is presented. The design and operation of the converter with details of control algorithm implementation and cooling chamber design are also discussed.
2014-09-16
Technical Paper
2014-01-2107
Michele Trancossi, Antonio Dumas, Carlos Xisto, Jose Pascoa, Andrea Andrisani
Abstract Rotocycloid propulsion presents interesting performance as a possible long-term alternative to helicopters in a far future. It will lead to increase the energy efficiency of VTOL vehicles. This paper focuses on optimization of an airship with the possibility up to 2000 h/year of photovoltaic propelled flight at a cruise speed about 20 m/s. This paper demonstrates the feasibility of this airship concept and presents a full dimensioning according to the CDE (Constructal Design for Efficiency) developed at University of Modena and Reggio Emilia. The proposed solution has been deeply analyzed and the analysis of performances has been presented. The results allow thinking to a novel class of vehicles designed specifically to take the maximum advantage by this propulsion method.
2014-09-16
Journal Article
2014-01-2123
Andre Hessling
Abstract Advanced technologies in LED's have the potential to reduce maintenance and improve aircraft safety. Aircrafts need adequate illumination for night time landing. New technology such as high-power LEDs allow for better suited light distributions, more whitish light compatible for mesopic lighting conditions and reduced glare in adverse weather conditions. LEDs and the associated electronics are more susceptible to harsh environmental conditions and this needs to be accounted for in the design of the equipment. Highly conductive metal core PCBs (MCPCB) allow for adequate cooling in a mirror telescopic optical arrangement when coupled with robust active cooling. Closed loop optical feedback of output flux ensures constant performance over the lifetime of the light unit and allows for indication of remaining useful life to the operator to plan maintenance activities. Parylene coating inhibits premature degradation of the LEDs induced by water vapor and corrosive gases.
2014-09-16
Technical Paper
2014-01-2127
Karl Strauss
Abstract “Today's electronic components rely on principles of physics and science with no manufacturing precedence and little data on long term stability and reliability.” [1] Yet many are counting on their reliable performance years if not decades into the future, sometimes after being literally abandoned in barns or stored neatly in tightly sealed bags. What makes sense? To toss everything away, or use it as is and hope for the best? Surely there must be a middle ground! With an unprecedented number of missions in its future and an ever-tightening budget, NASA faces the daunting task of doing more with less. One proven way for a project to save money is to use already screened and qualified devices from the spares of its predecessors. But what is the risk in doing so? How can a project reliably count on the value of spare devices if the risk of using them is not, in itself, defined?
2014-09-16
Technical Paper
2014-01-2125
Janice Meraglia, Mitchell Miller
Abstract Counterfeit items can be viewed as the by-product of a supply chain which has been compromised. While many industries are impacted, certain types of products can mean the difference between life and death. Electronics are of special interest, however, mechanical parts can also have dire consequences. The point is that the counterfeiting community is very diverse. The business model is fluid and unrestricted. Electronics today…hardware tomorrow. All of this leads to the need for an authentication platform that is agnostic to product. Most supply chains would benefit from a technical way to have assurance of authenticity - a benefit that could be shared by all.
2014-09-16
Technical Paper
2014-01-2115
Brian C. Raczkowski, Benjamin Loop, Jason Wells, Eric Walters, Oleg Wasynczuk, Sean Field, Jason Gousy
Abstract Future more electric aircraft (MEA) architectures that improve electrical power system's (EPS's) source and load utilization will require advance stability analysis capabilities. Systems are becoming more complex with bidirectional flows from power regeneration, multiple sources per channel and higher peak to average power ratios. Unknown load profiles with large transients complicate common stability analysis techniques. Advancements in analysis are critical for providing useful feedback to the system integrator and designers of multi-source, multi-load power systems. Overall, a framework for evaluating stability with large displacement events has been developed. Within this framework, voltage transient bounds are obtained by identifying the worst case load profile. The results can be used by system designers or integrators to provide specifications or limits to suppliers. Subsystem suppliers can test and evaluate their design prior to integration and hardware development.
2014-09-16
Technical Paper
2014-01-2113
Fei Gao, Serhiy Bozhko, Greg Asher
Abstract Stability is a great concern for the Electrical Power System (EPS) in the More Electric Aircraft (MEA). It is known that tightly controlled power electronic converters and motor drives may behave as constant power loads (CPLs) which may produce oscillations and cause instability. The paper investigates the stability boundaries for dc multi-source EPS under different power sharing strategies. For each possible strategy the corresponding reduced-order models are derived. The impedance criterion is then applied to study the EPS stability margins and investigates how these margins are influenced by different parameters, such as main bus capacitance, generator/converter control dynamics, cabling arrangements etc. These results are also illustrated by the root contours of reduced-order EPS models. Theoretical results achieved in the paper are confirmed by the time-domain simulations.
2014-09-16
Technical Paper
2014-01-2117
Michael L. Zierolf, Thomas Brinson, Andrew Fleming
Abstract Recent emphasis on optimization of engine technologies with ancillary subsystems such as power and thermal management has created a need for integrated system modeling. These systems are coupled such that federated design methods may not lead to the most synergetic solution. Obtaining an optimal design is often contingent on developing an integrated model. Integrated models, however, can involve combining complex simulation platforms into a single system of systems, which can present many challenges. Model organization and configuration control become increasingly important when orchestrating various models into a single simulation. Additionally, it is important to understand such details as the interface between models and signal routing to ensure the integrated behavior is not contaminated or biased. This paper will present some key learnings for model integration to help alleviate some of the challenges with system-based modeling.
2014-09-16
Technical Paper
2014-01-2176
Niloofar Rashidi Mehrabadi, Bo Wen, Rolando Burgos, Dushan Boroyevich, Chris Roy
Abstract The development of the concepts, terminology and methodology of verification and validation is based on practical issues, not the philosophy of science. Different communities have tried to improve the existing terminology to one which is more comprehensible in their own field of study. All definitions follow the same concept, but they have been defined in a way to be most applicable to a specific field of study. This paper proposes the Verification, Validation, and Uncertainty Quantification (VV&UQ) framework applicable to power electronic systems. Although the steps are similar to the VV&UQ frameworks' steps from other societies, this framework is more efficient as a result of the new arrangement of the steps which makes this procedure more comprehensible. This new arrangement gives this procedure the capability of improving the model in the most efficient way.
2014-09-16
Technical Paper
2014-01-2156
Arthur V. Radun
Abstract There is a continuing need to simulate power electronic circuits that include magnetic components. It is necessary to determine the interaction of the magnetic component with the rest of the power electronic system so that a dynamic circuit model of the magnetic components including material saturation and iron losses is required. Also, the magnetic component model must be valid when the magnetic component's excitation is not sinusoidal. A dynamic magnetic circuit model derived from Maxwell's equations along with useful theorems for building circuit models from the structure of the magnetic device is reviewed. The developed circuit models are general including magnetic saturation and iron losses. Simulation results for a DC/DC converter employing a conventional gapped inductor and a gapped coupled inductor are presented.
2014-09-16
Technical Paper
2014-01-2174
Nicholas Ernest, Kelly Cohen, Corey Schumacher, David Casbeer
Abstract Looking forward to an autonomous Unmanned Combat Aerial Vehicle (UCAV) for future applications, it becomes apparent that on-board intelligent controllers will be necessary for these advanced systems. LETHA (Learning Enhanced Tactical Handling Algorithm) was created to develop intelligent managers for these advanced unmanned craft through the novel means of a genetic cascading fuzzy system. In this approach, a genetic algorithm creates rule bases and optimizes membership functions for multiple fuzzy logic systems, whose inputs and outputs feed into one another alongside crisp data. A simulation space referred to as HADES (Hoplological Autonomous Defend and Engage Simulation) was created in which LETHA can train the UCAVs intelligent controllers.
2014-09-16
Technical Paper
2014-01-2152
Pedro Del valle, Pablo Blazquez Munoz
Abstract Advance thermal management systems are being developed to optimise the energy balance within aircraft. This is being done in parallel to the concept of the More Electrical Aircraft (MEA) which has been developing throughout the last decades. The objective of such complex systems is to use efficiently the hot and cold sources available within the air vehicle to reduce the engine fuel consumption. A reduction of electrical power consumption, minimisation of weight, optimisation of aircraft aerodynamics (for example RAM inlets area minimisation) and the reduction of bleed air from engine all result in a fuel consumption saving. Any thermal management system to optimise energy consumption implies complex and advanced systems. This requires a high engineering effort to design and integrate the system within an aircraft due to the large quantity of variables and interfaces that need to be taken into account.
2014-09-16
Technical Paper
2014-01-2164
Srikanth Gururajan, Mario Luca Fravolini, Matthew Rhudy, Antonio Moschitta, Marcello Napolitano
Abstract Recent catastrophic air crashes have shown that physical redundancy is not a foolproof option for failures on Air Data Systems (ADS) on an aircraft providing airspeed measurements. Since all the redundant sensors are subjected to the same environmental conditions in flight, a failure on one sensor could occur on the other sensors under certain conditions such as extreme weather; this class of failure is known in the literature as “common mode” failure. In this paper, different approaches to the problem of detection, identification and accommodation of failures on the Air Data System (ADS) of an aircraft are evaluated. This task can be divided into component tasks of equal criticality as Sensor Failure Detection and Identification (SFDI) and Sensor Failure Accommodation (SFA). Data from flight test experiments conducted using the WVU YF-22 unmanned research aircraft are used.
2014-09-16
Technical Paper
2014-01-2162
Viacheslav Pshikhopov, Mikhail Medvedev, Victor Krukhmalev, Roman Fedorenko, Boris Gurenko
Abstract The paper describes methods for control of docking of two moving stratospheric airships. One of them (cruiser) implements cruising flight at the defined altitude with defined velocity. The other one (feeder) fulfills the mission of chasing the cruiser with following docking operations. Mathematical model of exact airships are used in the work. Instances of structural and algorithmic implementation are based on position-trajectory controller. Simulation of docking control was accomplished with proposed methods.
2014-09-16
Technical Paper
2014-01-2142
Karen Davies, Patrick Norman, Catherine Jones, Stuart Galloway, Graeme Burt
Abstract Turboelectric Distributed Propulsion (TeDP) is actively being investigated as a means of providing thrust in future generations of aircraft. In response to the lack of published work regarding the system-level fault behaviour of a fully superconducting network, this paper presents key points from a two stage Failure Modes and Effects Analysis (FMEA) of a representative TeDP network. The first stage FMEA examines the qualitative behaviour of various network failure modes and considers the subsequent effects on the operation of the remainder of the network, enabling the identification of key variables influencing the fault response of the network. For the second stage FMEA, the paper focuses on the characterisation of the rate at which electrical faults develop within a TeDP network.
2014-09-16
Technical Paper
2014-01-2140
Kevin McCarthy, Patrick McCarthy, Ning Wu, Andrew Alleyne, Justin Koeln, Soumya Patnaik, Stephen Emo, Joshua Cory
Abstract As the cost and complexity of modern aircraft systems advance, emphasis has been placed on model-based design as a means for cost effective subsystem optimization. The success of the model-based design process is contingent on accurate prediction of the system response prior to hardware fabrication, but the level of fidelity necessary to achieve this objective is often called into question. Identifying the key benefits and limitations of model fidelity along with the key parameters that drive model accuracy will help improve the model-based design process enabling low cost, optimized solutions for current and future programs. In this effort, the accuracy and capability of a vapor cycle system (VCS) model were considered from a model fidelity and parameter accuracy standpoint. A range of model fidelity was evaluated in terms of accuracy, capability, simulation speed, and development time.
2014-09-16
Technical Paper
2014-01-2129
Vincent Metzger, Douglas Parker, Alain Philippe, Sebastien Claudot
Abstract Fiber optic physical contact connection technology has been used with multimode fiber in civilian aircraft for over 30 years with very good proven reliable performance. The extensive use of singlemode fiber (SMF) in FTTx Telecom market rollouts speeds up the development of passive optical components which significantly decreases the cost, expands capability and increases the reliability level of singlemode components. SMF transmission seems mandatory for future applications even in mil-aero and other harsh environment applications due to increased data rate requirements and new sensors applications. In harsh environment applications, is it realistic to use SMF with cores that are 30 times smaller in area compared to multimode fiber (MMF) when highly exposed to contamination? The present paper presents a technology of beam expansion interconnection that mixes a physical contact (PC) with an expanded optical surface.
2014-09-16
Technical Paper
2014-01-2150
Martin Bradish, Obed Sands, Ted Wright, Casey Bakula, Daniel Oldham, William Ivancic, Michael Lewis, Joseph Klebau, Nicholas Tollis, Andrew Jalics
Abstract This paper summarizes the Power, Avionics and Software (PAS) 1.0 subsystem integration testing and test results that occurred in August and September of 2013. This paper covers the capabilities of each PAS assembly to meet integration test objectives for non-safety critical, non-flight, non-human-rated hardware and software development. This test report is the outcome of the first integration of the PAS subsystem and is meant to provide data for subsequent designs, development and testing of the future PAS subsystems. The two main objectives were to assess the ability of the PAS assemblies' to exchange messages and to perform audio tests of both inbound and outbound channels. This paper describes each test performed, defines the test, the data, and provides conclusions and recommendations.
2014-09-16
Technical Paper
2014-01-2148
Jon Hagar
Abstract System testing can, in part, be defined as the application of concepts as an attempt to demonstrate that the implementation does not meet its intended use. Unfortunately, some industry verification test efforts only show that a system meets requirements which while necessary, are not sufficient to fully address a product's system-software testing. Managers, engineers, and testers may not be familiar with the wide variety of test concepts, approaches, and standards available for system-software testing-many of which can save projects money and effort in the long run. Newer software test standards and advanced techniques can offer a wealth of knowledge and improvement opportunities for software products.
2014-09-16
Technical Paper
2014-01-2146
Rudolf Neydorf, Sergey Novikov, Nikita Kudinov
Abstract Airship designers research application versions of systems with several ballonets for adjustment of airship roll and/or pitch as a whole. This requires effective automatic status management of each separate ballonet. But multi-ballonet system control issue encounters the absence of industrially measurable variables of each separate ballonet status. Thus status control issue of the system becomes uncertain. The fact requires the issue studying and shaping new scientific and technical solutions. This publication represents research results implying that fairly simple implementation and effective result can be achieved by application of fuzzy control concept. Its application is built on generating the representative quantity of fuzzy production rules. They are based on present set evaluation of known parameters and measured variables. This results in fuzzy but meaningful image of ballonet system status and airship as a whole.
2014-09-16
Journal Article
2014-01-2217
Javier Gazzarri, Nishant Shrivastava, Robyn Jackey, Craig Borghesani
Abstract Battery Management System (BMS) design is a complex task requiring sophisticated models that mimic the electrochemical behavior of the battery cell under a variety of operating conditions. Equivalent circuits are well-suited for this task because they offer a balance between fidelity and simulation speed, their parameters reflect direct experimental observations, and they are 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 employ a modeling and simulation approach that is capable of handling numerous simultaneous instances of the basic unit cell while maintaining real time performance.
2014-09-16
Technical Paper
2014-01-2213
Noriko Morioka, Hidefumi Saito, Norio Takahashi, Manabu Seta, Hitoshi Oyori
Abstract Electrical power management is a key technology in the AEA (All-Electric Aircraft) system, which manages the supply and demand of the electrical power in the entire aircraft system. However, the AEA system requires more than electrical power management alone. Adequate thermal management is also required, because the heat generated by aircraft systems and components increases with progressive system electrification, despite limited heat-sink capability in the aircraft. Since heat dissipation from power electronics such as electric motors, motor controllers and rectifiers, which are widely introduced into the AEA, becomes a key issue, an efficient cooling system architecture should be considered along with the AEA system concept. The more-electric architecture for the aircraft has been developed; mainly targeting reduced fuel burn and CO2 emissions from the aircraft, as well as leveraging ease of maintenance with electric/electronic components.
2014-09-16
Journal Article
2014-01-2227
Thierry Cornilleau, Pierre Linard, Paul Moxon, Christopher Nicholas
Abstract ECOA is an active software architecture research programme conducted by the French Republic and United Kingdom. It is one product of the recent Defence and Security Co-operation Treaty signed between the two nations. This paper provides an overview of the programme goals and progress as well as an introduction to the technology being developed and comparison to related initiatives. The goal of the ECOA programme is to define an open software architecture that enables collaborative development of mission system software. The ECOA programme is needed to reduce development and lifecycle costs of future military air programmes. For this reason the programme has a specific focus on combat-air mission systems but the underlying technology is general purpose, applying to multiple military and civil domains. At present, the programme has defined a concept, delivered a set of initial technical standards and produced a joint demonstrator to validate the technology developed.
2014-09-16
Technical Paper
2014-01-2188
Riko Bornholdt, Frank Thielecke
Abstract Due to a shift of the major aviation concerns to focus on enhancements of the successful programs instead of pushing their successors, the need for new methodologies for aircraft system architecture design emerges. Challenging the existing requirements and reconsidering the functions and their allocation could help to dissolve the system specific development paradigm and lead to beneficial architecture concepts. To help understand the mechanisms and boundary conditions of developing fault-tolerant systems, the first part of the paper gives an overview of the successive process of architecture design. The significant architectural design decisions and the concurrent safety assessment process are discussed. One crucial step in the design space exploration of future aircraft system architectures is the allocation of the consumers to the available power sources. Within the paper a methodology for the optimization of the power allocation for flight control systems is proposed.
2014-09-16
Technical Paper
2014-01-2186
Neno Novakovic
Abstract Since the early 1970s, when microprocessors became commercially available, they quickly became a common part of all aircraft control and indication systems. With an ever-increasing number of microprocessor-based airborne applications, safety regulations and software standards like RTCA DO-178 evolved, demanding rigorous requirements and processes for software development, testing, life cycle, and certification. Over the years, as development of aerospace software applications increased, engineering costs of development and product certification costs exponentially increased, having a significant impact on the market. Landing Gear Actuation system is one of many aircraft systems whose control functions are based on microprocessors and software application.
2014-09-16
Technical Paper
2014-01-2182
Evan Racine, Zachary Lammers, Street Barnett, John Murphy, Quinn Leland
Abstract The purpose of this study is to set up a laboratory test apparatus to analyze aircraft flight control EMAS' electrical and thermal energy flow under transient and dynamic flight profiles. A hydraulic load frame was used to exert load to the EMA. The actuator was placed within an environmental chamber which simulates ambient temperature as function of altitude. The simulated movement or stroke was carried out by the EMA. The under test EMA's dynamic load, stroke, and ambient temperature were synchronized through a real time Labview DAQ system. Motor drive voltage, current, regenerative current, and motor drive and motor winding temperature were recorded for energy analysis. The EMA under test was subjected to both transient and holding load laid out in a test matrix.
2014-09-16
Technical Paper
2014-01-2196
Massimo Conte, Michele Trancossi
Abstract This paper introduces a new equipment, which allows autonomous landing and docking of a VTOL aircraft and any mobile system. It has been studied and developed inside the MAAT (Multibody Advanced Airship for Transport) EU FP7 project to control autonomous docking of manned cruiser and feeder airships in movement. After a detailed analysis it has been verified that It could be considered a technological spin off the MAAT project. It defines a new instrumental system for governing relative positioning between a movable target and VTOL air vehicles, such as helicopters, airships and multi-copters. This solution is expected to become a short time to market equipment for helicopters (both manned and unmanned) ensuring autonomous landing ability even in case of low visibility. Infrared emitters allow controlling both position and yaws angle. It is in advanced testing phase after a preliminary successful testing using a quadcopter.
2014-09-16
Technical Paper
2014-01-2190
Michael Ellis, William Anderson, Jared Montgomery
Under a program funded by the Air Force Research Laboratory (AFRL), Advanced Cooling Technologies, Inc. (ACT) has developed a series of passive thermal management techniques for cooling avionics. Many avionics packages are often exposed to environment temperatures much higher than the maximum allowable temperatures of the electronics. This condition prevents the rejection of waste heat generated by these electronics to the surrounding environment and results in significant ambient heat gain. As a result, heat must be transported to a remote sink. However, sink selection aboard modern aircraft is limited at best. Often, the only viable sink is aircraft fuel and, depending on mission profile, the fuel temperature can become too high to effectively cool avionics. As a result, the electronic components must operate at higher than intended temperatures during portions of the mission profile, which reduces component lifetime and significantly increases the probability of failure.
2014-09-16
Technical Paper
2014-01-2192
Philip Abolmoali, Javier A. Parrilla, Awatef Hamed
Abstract The optimal integration of vehicle subsystems is of critical importance in the design of future energy efficient fighter aircraft. The INVENT (INtegrated Vehicle ENergy Technology) program has been dedicated to this endeavor through modeling/simulation of thermal management, power generation & distribution, & actuation subsystems. Achieving dual cooling & power generation capability from a single subsystem would be consistent with current efforts in system integration optimization. In this paper, we present a reconfiguration of an archetypal closed-loop air cycle system for a modern fighter as an open-loop gas generator cycle operating interchangeably between refrigeration and auxiliary power modes. A numerical model was developed within NPSS to assess maximum power extraction capabilities of a system originally designed for cooling purposes under different operating conditions.
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