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Viewing 241 to 270 of 21011
2014-09-16
Technical Paper
2014-01-2163
Mario Luca Fravolini, Matthew Rhudy, Srikanth Gururajan, Silvia Cascianelli, Marcello Napolitano
Abstract 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-static tube could induce an incorrect feedback control action, potentially leading to the loss of control of the UAV. 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-static tube sensor. The first approach is based on an Extended Kalman Filter (EKF) and the second approach is based on Least Squares (LS) modeling. The EKF technique utilizes nonlinear kinematic relations between GPS, Inertial Measurement Unit and Air Data System signals and has the advantage of independence from knowledge of the aircraft model. The LS method is based on explicit knowledge of the aircraft model and has the advantage of on-line computation of the airspeed estimate, with minimal computational effort.
2014-09-16
Technical Paper
2014-01-2143
Ralf D. Pechstedt
Abstract Recently, there has been an increasing interest in Fiber Optic Sensors (FOS) for aircraft applications. Many of the FOS are based on different transducer mechanisms and hence, 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. Oxsensis has been developing sensors for harsh environments with focus on land based gas-turbine monitoring and combustion control and more recently is also looking at applying its technology to other areas such as Aerospace and Oil & Gas. In this paper we report on recent progress on the development of a number of FOS and how these could find application in aircraft with a ‘universal interrogator’ concept in mind.
2014-09-16
Technical Paper
2014-01-2110
David Gras, Christophe Pautrel, Amir Fanaei, Gregory Thepaut, Maxime Chabert, Fabien Laplace, Gonzalo Picun
Abstract In this paper we present a set of integrated circuits specifically designed for high temperature power applications such as isolated power transistor drivers and high efficiency power supplies. The XTR26010 is the key circuit for the isolated power gate drive application. The XTR26010 circuit has been designed with a high focus in offering a robust, reliable and efficient solution for driving a large variety of high-temperature, high-voltage, and high-efficiency power transistors (SiC, GaN, Si) existing in the market. The XTR40010 is used for isolated data communication between a microcontroller or a PWM controller and the power driver (XTR26010). The isolated power transistor driver features a dual turn-on channel, a turn-off channel and a Miller Clamp channel with more than 3A peak current drive strength for each channel. The dV/dt immunity between XTR26010 and XTR40010 exceeds 50kV/μs. To demonstrate the performance and reliability at system level, a half-bridge driver test-board has been developed for driving SiC MOSFETs.
2014-09-16
Technical Paper
2014-01-2141
Christine Ross, Michael Armstrong, Mark Blackwelder, Catherine Jones, Patrick Norman, Steven Fletcher
Abstract The Turboelectric Distributed Propulsion (TeDP) concept uses gas turbine engines as prime movers for generators whose electrical power is used to drive motors and propulsors. For this NASA N3-X study, the motors, generators, and DC transmission lines are superconducting, and the power electronics and circuit breakers are cryogenic to maximize efficiency and increase power density of all associated components. Some of the protection challenges of a superconducting DC network are discussed such as low natural damping, superconducting and quenched states, and fast fault response time. For a given TeDP electrical system architecture with fixed power ratings, solid-state circuit breakers combined with superconducting fault-current limiters are examined with current-source control to limit and interrupt the fault current. To estimate the protection system weight and losses, scalable models of cryogenic bidirectional current-source converters, cryogenic bidirectional IGBT solid-state circuit breakers (CBs), and resistive-type superconducting fault current limiters (SFCLs) are developed to assess how the weight and losses of these components vary as a function of nominal voltage and current and fault current ratings.
2014-09-16
Technical Paper
2014-01-2194
Ralf Cremer, Alfred Engler
Abstract The application of power electronics in aircraft is increasing in the latest aircraft developments. This contribution focuses on the recent advances of activities at Liebherr-Elektronik GmbH linked to power electronics: active power filter based on fast silicon carbide switches, open box design for unpressurized area, light weight housing, EMC management, partial discharge detection and mitigation, arc-fault detection and standardized innovative power cores with optimized sensors. These topics are derived from a roadmap based on beforehand identified key drivers. These key drivers will enable the future More Electric Aircraft (MEA) by focusing on weight, reliability and cost. New technologies as Silicon Carbide (SiC) and advanced integration will support this strategy.
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. The impact of system quench and associated rise in network resistance as well as network parameters such as network voltage and pre-fault current, on the resulting fault profile are also examined using a range of sensitivity studies.
2014-09-16
Technical Paper
2014-01-2207
Evgeni Ganev, William Warr, Keming Chen
Abstract This paper presents a novel method and system for an electric power alternating-current (AC)-to-direct-current (DC) converter employing composite technology. The term composite entails utilization of more than one type of conversion operating in parallel. In addition, background information for the prior art, based on conventional autotransformer rectifier units (ATRUs), and active converters are discussed. The major requirements of AC-to-DC converters from both functional and protection perspectives are provided. The concept of the new approach is defined. Comparative analysis between the new and old methods is documented. The performance features and technical details of the system parameters with respect to AC-to-DC converter system requirements are presented and discussed. Analysis, simulation results, and test data are included. Finally, the advantages of this technology, which nearly doubles power density compared to the state-of-the-art, are summarized and a conclusion included.
2014-09-16
Technical Paper
2014-01-2167
Michael Usrey, Kevin Harsh, Alexander Brand, R. Steve McKown, Alireza Behbahani
Abstract Air Force Research Laboratory (AFRL) is pursuing development of advanced, distributed, intelligent, adaptive engine controls and engine health monitoring systems. The goals this pursuit are enhancing engine performance, safety, affordability, operability, and reliability while reducing obsolescence risk. The development of smart, high-bandwidth, high-temperature-operable, wide-range, pressure/temperature multi-sensors, which addresses these goals, is discussed. The resulting sensors and packaging can be manufactured at low cost and operate in corrosive environments, while measuring temperatures up to 2,552 °F (1,400 °C) with simultaneous pressure measurements up to 1,000 psi (68 atm). Such a sensor suite provides unprecedented monitoring of propulsion, energy generation, and industrial systems. The multi-sensor approach reduces control system weight and wiring complexity, design time, and cost, while increasing accuracy and fault tolerance. In situ pressure sensors reduce size and weight while eliminating failures associated with hypo-tube fouling.
2014-09-16
Technical Paper
2014-01-2132
Prashant Vadgaonkar, Ullas Janardhan, Adishesha Sivaramasastry
Abstract Performance of Avionics systems is dictated by the timely availability and usage of critical health parameters. Various sensors are extensively used to acquire and communicate the desired parameters. In today's scenario, sensors are hardwired. The number of sensors is growing due to automation which increases the accuracy of intended Aircraft functions. Sensors are distributed all over the Aircraft and they are connected through wired network for signal processing and communication. LRUs (Line Replaceable Unit) which are integrating various sensors also use a wired approach for communication. The use of a wired network approach poses challenges in terms of cable routing, stray capacitances, noise, mechanical structure and added weight to the structure. The weight of cables contributes significantly to the overall weight of the aircraft. As the weight of Aircraft increases, the required fuel quantity also increases. The Key driver for Airline operational cost is fuel. Fuel quantity is a direct function of weight.
2014-09-16
Technical Paper
2014-01-2206
Prashant Vadgaonkar
Abstract Today's digital avionics systems leverage the use of the Embedded COTS (Commercial Off The Shelf) hardware to fit the need of small form factor, low power, reduced time to market and reduced development time with efficient use of DO-254 for compliance of product. COTS modules are entering in digital avionics systems such as COM (Computer On Module)/SOM (System On Module)/SIP (System In Package) with huge advancement in semiconductor and packaging industry. In today's scenario COTS are very useful for DAL (Development Assurance Level) C and below as the efforts on compliance for DAL A and B are huge. This paper proposes to use these for DAL A and B as well, where one can get enormous benefit on efforts of compliance and time to market. This paper makes an attempt to explain the current scenario of the Embedded COTS usage in Avionics Systems. This paper also brings the study of the selection process of Embedded COTS along with the important selection parameters, constraints, challenges and guidelines.
2014-09-16
Technical Paper
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
2014-01-2144
Marco Amrhein, Jason Wells, Eric Walters, Seana McNeal, Brett Jordan, Peter Lamm
Abstract Transient operating conditions in electrical systems not only have significant impact on the operating behavior of individual components but indirectly affect system and component reliability and life. Specifically, transient loads can cause additional loss in the electrical conduction path consisting of windings, power electronic devices, distribution wires, etc., particularly when loads introduce high peak vs. average power ratios. The additional loss increases the operating temperatures and thermal cycling in the components, which is known to reduce their life and reliability. Further, mechanical stress caused by dynamic loading, which includes load torque cycling and high peak torque loading, increases material fatigue and thus reduces expected service life, particularly on rotating components (shaft, bearings). This article investigates the aforementioned stress mechanisms and provides analysis techniques and metrics to quantify the impact of transient operating conditions onto system and component reliability and life.
2014-09-15
Article
Germany's ZF has entered into a definitive agreement to acquire U.S.-based TRW Automotive Holdings Corp. for $13.5 billion, according to a Sept. 15 TRW press release. ZF has stated that TRW will be operated as a separate business division within ZF.
2014-09-15
Article
With the recent focus on the efficiency of vehicle electronics, automotive manufacturers are looking for tantalum capacitors with lower equivalent series resistance.
2014-09-15
Article
Excelfore enables simplified audio-video interconnectivity using Ethernet audio-video bridging, which leads to lower cost and system weight for infotainment systems in vehicles.
2014-09-15
Article
Sunex NoGhost 120dB lenses are the first and only lenses designed, optimized, and tested for use in cameras using high dynamic range image sensors, claims the company.
2014-09-15
Article
Q-Prime from Multek Flexible Circuits Inc. is a flexible circuit technology developed specifically for applications where efficient heat dispersion is required, and is especially useful for LED applications.
2014-09-15
Article
With its small size of 5.08 x 2.54 x 0.4 mm (0.20 x 0.10 x 0.02 in), high load capacity, and precision, Isabellenhütte’s gold-plated VMP-A resistor is suitable for automobile engine and transmission modules as well as power hybrids and power modules (DCB ceramic) in frequency converters. The VMP-A resistor is a member of the VMx precision resistor family with gold-plated contacts.
2014-09-12
Article
The new RR25 rotary speed sensor from Dynapar, which targets agricultural applications in the off-highway vehicle market, uses proven Hall-IC technology to provide reliable service in demanding environments where contaminants, corrosive chemicals, and high vibration are commonplace.
2014-09-12
Article
High-performance metamaterial antennas could be compact, lightweight, conformable, and stealthy.
2014-09-12
Standard
SSB1_001
This document is an annex to EIA Engineering Bulletin, SSB-1, Guidelines for Using Plastic Encapsulated Microcircuits and Semiconductors in Military, Aerospace and Other Rugges Applications (the latest revision). The scope of this document is to establish the recommended minimum qualification and monitoring testing of plastic encapsulated microcircuits and discrete semiconductors suitable for potential use in many rugged, military, severe, or other environments.
2014-09-12
Standard
SSB1_002
This document is an annex to EIA Engineering Bulletin SSB-1. Guidelines for Using Plastic Encapsulated Microcircuits and Semiconductors in Military, Aerospace and Other Rugged Applications. This document provides reference information concerning the environmental stresses associated with tests specifically designed to apply to (or have unique implications for) plastic encapsulated microcircuits and semiconductors, and the specific failures induced by these environmental stresses.
2014-09-12
Standard
SSB1_003A
This document is an annex to EIA Engineering Bulletin SAB-1, Guidelines for Using Plastic Encapsulated Microcircuits and Semiconductors in Military, Aerospace and Other Rugged Applications (the latest revision). This document provided reference information concerning acceleration factors commonly used by device manufacturers to model failure rates in conjunction with statistical reliability monitoring. These acceleration factors are frequently used by OEMs in conjunction with physics of failure reliability analysis to assess the suitability of plastic encapsulated microcircuits and semiconductors for specific end use applications.
2014-09-11
Standard
AS81714B
This specification covers Terminal Junction System (TJS) components which are used for interconnection of wiring and incorporation of passive components (see 6.1). These environment resistant components have in common the use of crimp type external pin contacts in accordance with AS39029/1 for Series I or crimp type external socket contacts in accordance with AS39029/22 for Series II. This family of TJS components is designed to operate continuously over a temperature range of -65 to 200 °C, using any combination of temperatures generated by the electrical load and ambient temperature so that the maximum internal hot spot, combined temperature, will not exceed the maximum specified for the class of TJS component, unless otherwise specified.
2014-09-11
WIP Standard
AS31021B
No scope available.
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