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Viewing 61 to 90 of 21997
2015-09-15
Technical Paper
2015-01-2533
Philippe Coni, Frederic Merino, Frederic Renaud
Projected capacitive touchscreen (PCT) became popular thanks to the introduction of the Apple iPhone, iPad and iPod. Electrical field generated for touch detection is known to be impaired by external fields, for example Cold Cathode Fluorescent Lamp, USB charger or AMLCD driving. Commercial product shall live with this issue, but the high intensity radiated field required for avionics application is several orders of magnitude higher than required for commercial product. In such an environment, standard touchscreens could have hazardous behavior. Thanks to the unique 20 years’ experience on projected capacitive technology (Aircraft fighter RAFALE), we designed a new projected capacitive touchscreen, based on a ruggedized touch controller and dedicated ASIC, able to operate in extreme electromagnetic environment.
2015-09-15
Technical Paper
2015-01-2537
Sylvain Hourlier
The efficiency of the glass cockpit paradigm has faded away with the evolution of the aeronautical environment (traffic increase & permanence of service). Today's problem lies with "non-defective aircraft" monitored by "perfectly trained crews" still involved in fatal accidents. One explanation is, at the crew level, that we have reached a system complexity that, while acceptable in normal conditions, is hardly compatible with human cognitive abilities in degraded conditions. The current mitigation of such risk still relies on the enforcement through intensive training of an ability to manage extremely rare (off-normal) situations. These are explained by the potential combination of failures of highly complex systems with variable environment & with variable humans.
2015-09-15
Technical Paper
2015-01-2532
Sylvain Hourlier, Sandra Guérard, Jean Luc BAROU, Xavier Servantie
As touch screens are everywhere in the consumer market Thales has launched in depth evaluations on their introduction in the cockpit. One of the challenges is to verify its compatibility with in flight use under turbulence conditions, including light, moderate and severe. In flight accelerometer collections were performed to provide us with a baseline for choosing between possible simulation solutions. Thales recognized early on the need for such a tool as it would enable us to define recommendations for our HMI designs. The objectives were first to validate specific complex touch/gestures using all the potential of touch interactions for novel cockpit Human Machine Interfaces and second to look into the various physical anchoring solutions capable of facilitating touch screens interactions in aeronautical turbulent environments. Given the 6 axis accelerometer profiles that were collected, a number of potential candidate simulation platforms were selected.
2015-09-15
Technical Paper
2015-01-2549
Marc-André Léonard, Jean-François Boland, Christophe Jégo, Claude Thibeault
Nowadays, growing complexity in digital systems forces electronic hardware designers to adopt Electronic System Level (ESL) design and verification approach from a high-level perspective. To assess the reliability of a digital hardware design towards cosmic rays effects, this paper proposes a verification methodology based on high abstraction level fault injection simulation using a library of primitives characterized at lower levels. Once created, the designer can reuse this library in order to obtain a reliability report. The novelty of this research resides in the capacity of using an accurate fault injection model in a highly abstracted system description. Combining this accuracy with the use of error pattern classification at low-level, brings a new perspective to the simulation-based fault injection field.
2015-09-15
Technical Paper
2015-01-2551
Ephraim Suhir, Alain Bensoussan
In some today’s and future optoelectronic packaging systems, including those intended for aerospace applications, the package (system’s component containing active and/or passive devices and interconnects) is placed (“sandwiched”) between two substrates, which, in an approximate analysis, could be considered identical. Such a system is bow-free. This might be an important merit that could be helpful in maintaining high coupling efficiency in warpage-sensitive optical devices. The highest thermal stresses in such a tri-component (one inner and two outer components) bi-material (the composite material of the inner component - package and of the material of the outer components - substrates) assembly occur at low temperature conditions, are caused by the thermal contraction mismatch of the dissimilar materials of the assembly components and include normal stresses acting in the cross-sections of the components, and interfacial shearing and peeling stresses.
2015-09-15
Technical Paper
2015-01-2542
Alejandro Murrieta-Mendoza, Ruxandra Mihaela Botez, Roberto S Félix Patrón
Flight trajectory optimization algorithms reduce flight cost regardless of the aircraft technologies. Besides flight cost reduction, diminishing fossil fuel consumption leads to reducing polluting emissions. Ground teams and avionic equipment such as the flight management system seek for the routes that minimize the flight cost. The flight plan also contains the trajectory information in the form of waypoints to follow. This plan is provided to the pilot and is introduced into the flight management system. The flight plan contains as well weather information such as wind and temperature. In this paper, genetic algorithms were applied to the waypoints available in the flight plan to find the combination of altitudes that minimize the flight time and fuel burned. In the literature trajectories are normally taken from radar date, or the geodesic route between two points amongst others. Published waypoints are seldom used.
2015-09-15
Technical Paper
2015-01-2555
Ephraim Suhir
It has been lately established (see, e.g., [1]) that the continuing trend on miniaturization (Moore’s Law) in IC design and fabrication might have a negative impact on the device reliability, especially when it comes to deep submicron (DSM) technologies. These are characterized by etching thicknesses below 90nm. In order to understand and to quantify the physics underlying this phenomenon, it is natural to proceed from the experimental bathtub curve (BTC), an experimental reliability “passport” of a population of mass produced devices. As is known, this curve considers and reflects the combined effect of two irreversible processes: statistics-related mass-production process and reliability-physics-related degradation (aging) process. The first process results in a decreasing failure rate with time, while the second process leads to an increasing failure rate. It is this second process that should be of major concern to an IC designer and manufacturer.
2015-09-15
Technical Paper
2015-01-2558
Jörg Brauer, Markus Dahlweid, Jan Peleska
The DO-178C requires data and control coupling (DC/CC) analysis to be performed as part of the validation activities. Here, “data coupling” between software components is defined as the dependence of a component on data that is not exclusively under the control of that component. Likewise, “control coupling” is defined as the degree by which one component influences the execution of another component. The intent of DC/CC analysis is then to provide assurance of the correctness of the interactions between different components, which can for example be achieved by integration tests. Unfortunately, DC/CC analysis has often been misunderstood as a review activity to ensure that the code correctly implements the design, whilst its de-facto purpose is to validate the verification activities.
2015-09-15
Technical Paper
2015-01-2539
Alessandro Gardi, Roberto Sabatini, Subramanian Ramasamy, Matthew Marino, Trevor Kistan
The potential benefits offered by advanced aircraft navigation technologies will be ultimately exploited only through the dynamic allocation of resources in a highly automated airspace. In this respect, the deployment of Four Dimensional Trajectory (4DT) functionalities in an Intent Based Operations (IBO) environment is envisaged as a fundamental enabler of future Air Traffic Management (ATM) services. The 4DT-IBO, in turn, are requiring the introduction of novel Communications, Navigation and Surveillance and ATM (CNS/ATM) systems, enabling the migration from traditional voice communications to data-driven negotiation and validation functions. A novel ground-based 4DT Planning, Negotiation and Validation (4-PNV) system is being developed in conjunction with Next Generation Flight Management Systems (NG-FMS) and Mission Management Systems (NG-MMS) for integration into the future air traffic scenario.
2015-09-15
Technical Paper
2015-01-2459
Francesco Cappello, Subramanian Ramasamy, Roberto Sabatini
Multi-sensor navigation systems involving satellite-based and inertial sensors are widely adopted to improve the stand-alone navigation solution for a number of mission- and safety-critical applications. However such integrated Navigation and Guidance Systems (NGS) do not meet the required level of performances in all flight phases, specifically for precision approach and landing tasks. In this paper an innovative Square Root-Unscented Kalman Filter (SR-UKF) based NGS architecture for small-to-medium size Remotely Piloted Aircraft System (RPAS) is presented and compared with Unscented Kalman Filter (UKF) based design. These systems are based on an advanced approach for data fusion involving low-cost sensors including Global Navigation Satellite Systems (GNSS), Micro-Electro-Mechanical System (MEMS) based Inertial Measurement Unit (IMU) and Vision Based Navigation (VBN) sensors.
2015-09-15
Technical Paper
2015-01-2475
Francesco Cappello, Roberto Sabatini, Subramanian Ramasamy
Accurate and robust tracking of objects is of growing interest among the computer vision scientific communities. The ability of a vision system to detect and track the objects, and accurately predict their future trajectory is critical in the context of mission- and safety-critical applications. Remotely Piloted Aircraft Systems (RPAS) are not currently equipped to routinely access all classes of airspace and thus providing the pathway to coexist seamlessly with manned aircraft. Such capabilities can be achieved by incorporating both cooperative and non-cooperative Detect-And-Avoid (DAA) functions, as well an providing enhanced communications, navigation and surveillance (CNS) services. DAA is highly dependent on the performance of CNS systems, specifically for Tracking, Deciding and Avoidance (TDA) tasks.
2015-09-15
Technical Paper
2015-01-2544
Subramanian Ramasamy, Roberto Sabatini
Novel Communication, Navigation, Surveillance/Air Traffic Management (CNS/ATM) systems are currently developed, in line with the roadmap defined by large-scale research initiatives including Single European Sky ATM Research (SESAR) in Europe, Next Generation Air Transportation System (NextGen) in US, and other programmes worldwide. The demand for improved safety, integrity and efficiency due to the rapid expansion of global air transport and the growing concern for environmental sustainability issues poses significant challenges on the development of CNS/ATM and Avionics (CNS+A) systems. High-integrity and high-reliability mission- and safety-critical ATM and avionic systems are therefore required in the context of Four Dimensional (4D) Trajectory Based Operations / Intent Based Operations (TBO/IBO).
2015-09-15
Technical Paper
2015-01-2541
Alejandro Murrieta-Mendoza, Ruxandra Botez
Flight trajectory optimization has been identified as a way to reduce flight costs and to diminish polluting emissions to the atmosphere due to fuel powered engines. The Flight management system is a device that among its functions is in charge of flight optimization. This paper presents an optimization algorithm that solved the Vertical Navigation problem by providing the combinations of climb, cruise and descent speeds along with altitudes the aircraft should follow to minimize the flight cost. Due to flight management system computation power limitations, this algorithm aims to find the solution with just little calculations. The developed algorithm took advantage of a space search reduction algorithm to reduce the initial number of speed/altitude combinations available since the first iteration. Additional search space reductions were performed with the implementation of the branch and cut algorithm.
2015-09-15
Technical Paper
2015-01-2583
James Hare, Shalabh Gupta, Nayeff Najjar, Paul D'Orlando, Rhonda Walthall
This paper addresses the issue of detecting and isolating faults in complex networked systems. Complex Networked Systems typically contain multiple subsystems, components, and sensors interconnected through feedback control and thermal couplings. When a fault occurs in a component of a complex networked system, the effects of the fault may cause offnominal operations in other components due to fluctuations in their input signals. Health monitoring algorithms developed in literature typically result in false alarms during these scenarios since the data observed through sensor measurements are showing unhealthy characteristics even though the components are performing correctly given their offnominal input signals. This paper proposes a System Level Isolation and DEtection (SLIDE) algorithm that will detect and isolate faults occurring in multiple subsystems while reducing the computational complexity and minimizing false alarms.
2015-09-15
Technical Paper
2015-01-2587
Matthew Smith, Peter F. Sulcs, Rhonda Walthall, Mark Mosher, Gregory Kacprzynski
Aircraft System Health Management (ASHM) is a UTC developed web application that provides access to Aircraft Condition Monitoring Function (ACMF) reports and Flight Deck Effects (FDE) records for B787 and A320 a/c. The tool was built with a flexible architecture to field a range of off-board diagnostics and prognostics modules designed to transform an abundance of data into actionable and timely knowledge about fleet health. This paper describes the ASHM system architecture and implementation with a focus on “lessons learned” in applying diagnostic and prognostics algorithms to available fleet data. Key topics include managing data quality issues, design for cross-enterprise collaboration and defining a workable approach to testing, validating and deploying prognostics and diagnostics models with various degrees of complexity. A case study is provided related to fluid leak detection within an environmental control subsystem.
2015-09-06
Technical Paper
2015-24-2544
Fernando Ortenzi, Giovanni Pede, Pierluigi Antonini
Within the “Industria 2015” Italian framework program, the HI-ZEV project has the aim to develop two high performance vehicles: one full electric and one hybrid. The hybrid vehicle is a sport car with an internal combustion engine with a maximum power of 300 kW and an electric motor with a maximum power of 150 kW. It is equipped with a 400 V, 15 Ah storage system. Special batteries are required due to the high values of discharge current needed to supply the electric subsystem (up to 25 times the nominal current). Also a dedicated cooling system has been designed, to avoid a dangerous rising temperature, due to such high currents. The cells used have been the Demon 5Ah OCCL (Oxygen-Cobalt-Carbon-Li-Ion technology). Every single module is composed by 6 cells in series with 22.5V of nominal voltage, while the battery pack is made with 18 modules in series and 3 in parallel.
2015-09-06
Technical Paper
2015-24-2418
Zheming Li, Xin Yu, Guillaume Lequien, Ted Lind, Marcis Jansons, Oivind Andersson, Mattias Richter
Abstract The presence of OH radicals as a marker of the high temperature reaction region usually has been used to determine the lift-off length (LOL) in diesel engines. Both OH Laser Induced Fluorescence (LIF) and OH* chemiluminescence diagnostics have been widely used in optical engines for measuring the LOL. OH* chemiluminescence is radiation from OH being formed in the exited states (OH*). As a consequence OH* chemiluminescence imaging provides line-of-sight information across the imaged volume. In contrast, OH-LIF provides information on the distribution of radicals present in the energy ground state. The OH-LIF images only show OH distribution in the thin cross-section illuminated by the laser. When both these techniques have been applied in earlier work, it has often been reported that the chemiluminescence measurements result in shorter lift-off lengths than the LIF approach.
2015-09-06
Technical Paper
2015-24-2438
Maria Founti, Yannis Hardalupas, Christopher Hong, Christos Keramiotis, Kumara Gurubaran Ramaswamy, Nikolaos Soulopoulos, Alexander Taylor, Dimitrios P. Touloupis, George Vourliotakis
The present work investigates the effect of low levels CO2 addition on the combustion characteristics inside a single cylinder optical engine operated under low load conditions. The effects of dilution levels (up to 7.5% mass flow rate CO2 addition), the number of pilot injections (single or double pilot injections) and injection pressure (25 or 40 MPa), are evaluated towards the direction of achieving a partially premixed combustion (PPC) operation mode. The findings are discussed based on optical measurements and via pressure trace and apparent rate of heat release analyses in a Ricardo Hydra optical light duty diesel engine. The engine was operated under low IMEP levels of the order of 1.6 bar at 1200 rpm and with a CO2 diluent-enhanced atmosphere resembling an environment of simulated low exhaust gas recirculation (EGR) rates. Flame propagation is captured by means of high speed imaging and OH, CH and C2 line-of-sight chemiluminescence respectively.
2015-09-06
Technical Paper
2015-24-2473
Alessandro Montanaro, Luigi Allocca, Giovanni Meccariello, Maurizio Lazzaro
Abstract In internal combustion engines, the direct injection at high pressures produces a strong impact of the fuel on the combustion chamber wall, especially in small-bore sizes used for passenger cars. This effect is relevant for the combustion process resulting in an increase of the pollutant emissions and in a reduction of the engine performances. This paper aims to report the effects of the injection pressure and wall temperature on the macroscopic behavior and atomization of the impinging sprays on the wall. The gasoline spray-wall interaction was characterized inside an optically accessible quiescent chamber using a novel make ready Z-shaped schlieren-Mie scattering set-up using a high-speed C-Mos camera as imaging system. The arrangement was capable to acquire alternatively the schlieren and Mie-scattering images in a quasi-simultaneous fashion using the same line-of-sight.
2015-09-06
Technical Paper
2015-24-2405
Michela Costa, Daniele Piazzullo, Ugo Sorge, Simona Merola, Adrian Irimescu, Vittorio Rocco
Abstract Ignition and flame inception are well recognised as affecting performance and stable operation of spark ignition engines. The very early stage of combustion is indeed the main source of cycle-to-cycle variability, in particular in gasoline direct injection (GDI) engines, where mixture formation may lead to non-homogenous air-to-fuel distributions, especially under some speed and load conditions. From a numerical perspective, 3D modelling of combustion within Reynolds Averaged Navier Stokes (RANS) approaches is not sufficient to provide reliable information about cyclic variability, unless proper changes in the initial conditions of the flow transport equations are considered. Combustion models based on the flamelet concept prove being particularly suitable for the simulation of the energy conversion process in internal combustion engines, due to their low computational cost.
2015-09-06
Journal Article
2015-24-2442
Guillaume Lequien, Zheming Li, Oivind Andersson, Mattias Richter
Abstract The influence of jet-flow and jet-jet interactions on the lift-off length of diesel jets are investigated in an optically accessible heavy-duty diesel engine. High-speed OH chemiluminescence imaging technique is employed to capture the transient evolution of the lift-off length up to its stabilization. The engine is operated at 1200 rpm and at a constant load of 5 bar IMEP. Decreasing the inter-jet spacing shortens the liftoff length of the jet. A strong interaction is also observed between the bulk in-cylinder gas temperature and the inter-jet spacing. The in-cylinder swirl level only has a limited influence on the final lift-off length position. Increasing the inter-jet spacing is found to reduce the magnitude of the cycle-to-cycle variations of the lift-off length.
2015-09-06
Technical Paper
2015-24-2455
Slavey Tanov, Zhenkan Wang, Hua Wang, Mattias Richter, Bengt Johansson
Abstract Partially premixed combustion (PPC) is used to meet the increasing demands of emission legislation and to improve fuel efficiency. With gasoline fuels, PPC has the advantage of a longer premixed duration of the fuel/air mixture, which prevents soot formation. In addition, the overall combustion stability can be increased with a longer ignition delay, providing proper fuel injection strategies. In this work, the effects of multiple injections on the generation of in-cylinder turbulence at a single swirl ratio are investigated. High-speed particle image velocimetry (PIV) is conducted in an optical direct-injection (DI) engine to obtain the turbulence structure during fired conditions. Primary reference fuel (PRF) 70 (30% n-heptane and 70% iso-octane) is used as the PPC fuel. In order to maintain the in-cylinder flow as similarly as possible to the flow that would exist in a production engine, the quartz piston retains a realistic bowl geometry.
2015-09-06
Technical Paper
2015-24-2454
Zhenkan Wang, Slavey Tanov, Hua Wang, Mattias Richter, Bengt Johansson, Marcus Alden
It has been proven that partially premixed combustion (PPC) has the capability of high combustion efficiency with low soot and NOx emissions, which meet the requirements of increasingly restricted emission regulations. In order to obtain more homogenous combustion and longer ignition delay in PPC, different fuel injection strategies were employed which could affect the fuel air mixing and control the combustion. In the present work, a light duty optical diesel engine was used to conduct high speed particle image velocimetry (PIV) for single, double and triple injections with different timings. A quartz piston and a cylinder liner were installed in the Bowditch configuration to enable optical access. The geometry of the quartz piston crown is based on the standard diesel combustion chamber design for this commercial passenger car engine, including a re-entrant bowl shape.
2015-08-20
Technical Paper
2015-28-0002
Abhijit Kulkarni, Vinod John
Second-order generalized integrator (SOGI) based phase-locked loops (PLLs) are used for grid voltage synchronization in single-phase grid-connected power converters. SOGI-PLLs are attractive because of the simple structure and the suitability for implementation in low-end digital controllers. In this paper, a cascaded SOGI-PLL structure is discussed, with full offset rejection capability. A systematic design procedure is proposed for this PLL minimizing the response time and unit vector harmonic distortion. This design achieves minimum settling time for a given level of frequency deviation of the grid voltage. The PLL designed using the proposed method has sufficient harmonic attenuation capability. The analytical predictions are verified experimentally.
2015-08-20
Technical Paper
2015-28-0006
V. S. S. Pavan Kumar Hari, Avanish Tripathi, G Narayanan
High-performance industrial drives widely employ induction motors with position sensorless vector control. The speed controller design in such a drive is highly sensitive to the mechanical parameters of the induction motor. This paper proposes a method to determine the mechanical parameters, namely the moment of inertia and frictional coefficient of the induction motor drive. The proposed method is based on acceleration and deceleration of the motor under constant torque, which is achieved using a sensorless vector-controlled drive itself. Experimental results from a $5$hp induction motor drive are presented.
2015-08-20
Technical Paper
2015-28-0009
Shimin V V, Varsha Shah, Makrand Lokhande
In the current world scenario of increasing environmental issues and oil prices, development of electric vehicles (EV) have gained considerable importance and attention. Power electronics will play a key role in making highly efficient electric vehicles which are low in emissions and having better fuel economy. This paper presents a review of the state of the art of power electronics technology in electric vehicles and also discusses the role of power electronics in achieving the vision of Indian Government in the field of EVs by 2020. The paper concludes with a discussion of expected future trends in power electronics technology that will improve the markets for electric vehicles in coming years.
2015-08-20
Technical Paper
2015-28-0011
Sathiyaraj Asaithambi, Amitabh Vaidya, Riaz Ahamed
Component level validation plays a very important role in an Electric Vehicles during development of a new platform.. Validating the product for their mission life and finding the early failures that can occur in field and correcting the failures at early stages proves to be very helpful in improving product Reliability and confidence. Product durability test is one of the most important tests in validation. Durability testing is the evaluation of duration of time that a product, part, material, or system can meet its performance requirements against its mission life. Durability is conducted on every component, module and also at system and vehicle level. Transmission is commonly used in all the automobile vehicles to transmit power. Transmission in Electric vehicle is a single gear ratio, two stage transmission transmitting power from motor to axle.
2015-08-20
Technical Paper
2015-28-0013
Preeti Agarwal, Vineeta Agarwal
For rural or remote areas the single-phase grid has been considered as an alternative especially when compared with the three-phase solution due to its lower cost feature. The loads connected in a three-phase arrangement present some advantages when compared with single-phase loads especially for motors due to their constant torque, constant power, reduced size, etc. High speed machines are used in different applications such as dental drills and medical surgery tools, compressors and turbochargers, blowers, turbo molecular vacuum pumps, compact electrical power suppliers and micro co-generation gas turbines, aircraft electrical starter generator systems, flywheel energy storages and machine tool spindles and electric propulsion systems. This paper proposes a single-phase to three-phase Cycloinverter capable of generating high frequency three-phase output using self-commutated semiconductor devices.
2015-08-20
Technical Paper
2015-28-0012
Dheeraj Narang, Subhash Chavadaki
Bicycles were introduced in the 19th century in Europe and now number more than a billion worldwide, twice as many as automobiles. This document gives information about the usage of powered bicycles based on renewable energy systems. The renewable energy which is discussed in this paper is using solar energy. Solar panels are an effective and efficient way of using solar energy. The bicycle uses the solar panels to charge the batteries which intern are used to power a motor, driving the bicycles. It also gives a report on the efficiency of batteries and solar panels. Explanatory material is followed by a worked example.
2015-08-20
Technical Paper
2015-28-0017
Jiten Chavda, Varsha Shah, Makrand Lokhande, Rakeshkumar Shankar
This paper presents the speed control of sensored BLDC motor using PWM techniques. The BLDC motor with EV or HEV application uses the position sensor for the operation and speed control of motor. In this paper the simulation of BLDC motor is done using soft commutating technique (Proteus Design Suit & Keil uVision3 software). A prototype is implemented to verify the performance of proposed new approach for control of sensored BLDC motor of 48V, 5A, 250W manufactured for E-BIKES. The speed control and real time measurement is obtained and compared and found satisfactory performance.
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