Display:

Results

Viewing 1 to 30 of 3428
2017-03-28
Technical Paper
2017-01-0113
Vaclav Jirovsky
Today's vehicles are being more often equipped with systems, which are autonomously influencing the vehicle behavior. The close future is awaiting more systems of the kind and even significant penetration of fully autonomous vehicles in regular traffic is expected by OEMs in Europe around year 2025. The driving is highly multitasking activity and human errors emerge in situations, when he is not able to process and understand the essential amount of information. Future autonomous systems very often rely on some type of inter-vehicular communication. This shall provide the vehicle with similar or higher amount of information, than driver uses in his decision making process. Therefore, currently used, and debatable, 1-D quantity TTC (time-to-collision) will definitely become inadequate. Regardless the vehicle is driven by human or robot, it’s always necessary to know, whether and which reaction is necessary to perform.
2017-03-28
Technical Paper
2017-01-0025
Takayuki Kitamura, Naotsugu Shimizu, Yasuyuki Miyake
In the last decade, radar-based Advanced Driver Assistance Systems(ADAS) have improved transportation safety. And today, the standardization of ADAS by NCAP is expected to expand its market globally. One of the key technology for ADAS is rear-side monitoring system enabling application such as Blind Spot Warning(BSW) and Lane Change Warning(LCW). It is desired to expand the detection range so that it can monitor not only nearside targets widely for BSW but farther targets for LCW. These applications can be achieved by using two radar sensors installed at rear-side corner of the vehicle. However, wider and farther detection range causes the undesirable target detection and decreases target recognition performance. In this paper, a novel solution to improve the performance by using 2FCW-based Beamspace technology is introduced. Combined with IQ detector, 2FCW receiver outputs beat signal proportional to the relative speed of an object.
2016-10-25
Technical Paper
2016-36-0282
Suely M. C. Romeiro, Marcelo L. de Oliveira e Souza
Abstract Modeling and Simulation - M&S is recently gaining more importance and emphasis as an essential method for developing engineering systems especially for aerospace and automotive systems, due to their complexity, integration and even human involvement. The main reasons for M&S having that important role nowadays are: 1) M&S can predict system behavior and possible problems. Therefore, it can reduce time and cost for developing systems, it can avoid future corrections into systems, as well. 2) M&S can be used for conception, training, maintenance, etc., requiring less expensive tools and previously preparing people to the real scenario. 3) When it comes to situations that involve aerospace or other products, where high costs are involved, mistakes can be avoided or at least minimized. Summarizing, M&S can reduce project cost and schedule, and improve quality.
2016-10-25
Technical Paper
2016-36-0377
Alain Giacobini Souza, Luiz Carlos Gadelha Souza
Abstract In designing of the Attitude Control System (ACS) is important take into account the influence of the structure’s flexibility, since they can interact with the satellite rigid motion, mainly, during translational and/or rotational maneuver, damaging the ACS pointing accuracy. In the linearization and reduction of the rigid-flexible satellite mathematic model, usually one loses some important information associated with the satellite true dynamical behavior. One way to recovery this information is include to the ACS design parametric and not parametric uncertainties of the system. The H infinity control method is able to take into account the parametric uncertainty in the control law design, so the controller becomes more robust. This paper presents the design of a robust controller using the H infinity control technique to control the attitude of a rigid-flexible satellite.
2016-10-25
Technical Paper
2016-36-0402
Jairo Cavalcanti Amaral, Marcelo Lopes de Oliveira e Souza
Abstract Switching controls are those that can switch between control or plant modes to perform their functions. They have the advantage of being simpler to design than an equivalent control system with a single mode. However, the transients between those modes can introduce steps or overshootings in the state variables, and this can degrade the performance or even damage the control or the plant. So, the smoothing of such transients is vital for their reliability and mantainability. This is can be of extreme importance in the aerospace and automotive fields, plenty of switchings between manual and autopilot modes via relays, or among gears via clutches, for example. In this work, we present a first strategy for smoothing transients in switching controls of aerospace and automotive systems.
2016-10-25
Technical Paper
2016-36-0293
Eloy Martins de Oliveira Junior, Marcelo Lopes de Oliveira e Souza
Abstract Cyber-physical systems are joint instances of growing complexity and high integration of elements in the information and physical domains reaching high levels of difficulty to engineer an operate them. This happens with satellites, aircraft, automobiles, smart grids and others. Current technologies as computation, communication and control integrate those domains to communicate, synchronize and operate together. However, the integration of different domains brings new challenges and adds new issues, mainly in real time distributed control systems, beginning with time synchronization. In this paper, we present a discussion on time synchronization and their effects in distributed cyber-physical control systems. To do that, we review the literature, discuss some time synchronization techniques used in cyber-physical systems, and illustrate them via model and simulation of a system representative of the aerospace area.
2016-09-27
Technical Paper
2016-01-2107
Rainer Mueller, Matthias Vette, Matthias Scholer, Jan Ball
Abstract The global competition challenges aircraft manufactures in high wage countries. The assembly of large components is very difficult and distinguished by fixed position assembly. Many complex assembly processes such as aircraft assembly are manually done by highly skilled workers. The aircraft manufactures deal with a varying number of items, increasing number of product variants and strict product requirements. During the assembly process hundreds of clips, ties and stringers as well as thousands of rivets must be assembled. To remain competitive in global competition, companies in high wage countries like Germany must insure a continuously high productivity and quality level. To achieve a reduction of cycle times with a simultaneous increase in quality, supportive assistance systems for visual support, documentation and organization within the assembly are required. One example for visual assistance systems are laser projection systems.
2016-09-27
Technical Paper
2016-01-2117
Rustam M. Baytimerov, Pavel Lykov, Sergei Sapozhnikov, Dmitry Zherebtsov, Konstantin Bromer
Abstract The development of Additive Technologies (SLS/SLM, EBM, DMD) suggests the increase of range expansion of materials used. One of the most promising directions is products manufacturing from composite materials. The technology of composite micro-powders production on the basis of heat-resistant nickel alloy EP648 and Al2O3 is proposed. The aim of this research is to develop a method of producing composite micropowders for additive technology application. This method is based on modification of the metal micropowders surface by the second phase in a planetary mixer (mechanochemical synthesis).The obtained composite micropowders are compared with powders which are recommended for selective laser melting usage (produced by MTT Technology). The equipment used in the research: planetary mixer, scanning electron microscopy (SEM), optical granulomorphometer Occio 500nano.
2016-09-27
Technical Paper
2016-01-2121
Pavel Lykov, Rustam M. Baytimerov, Artem Leyvi, Dmitry Zherebtsov, Alexey Shultc
Abstract The copper-nickel alloys are widely used in various industries. The adding of nickel significantly enhances mechanical properties, corrosion resistance and thermoelectric properties of copper. The technology was proposed of production of copper-nickel composite micro-powders by the gaseous deposition of nickel on the surface of copper powder. The vaporization of nickel was implemented by using magnetron. The relationship between mode of processing and the ratio of phases in the powder was investigated. The proposed method allows to modify the powder surface without deformation of the particles. The possibility of using of obtained composite powder in selective laser melting (SLM) was evaluated. It is assumed that the structure of the obtained composite material (SLM) will have inclusions of nickel and continuous chain of copper. This structure will have high mechanical properties and high electrical conductivity.
2016-09-27
Technical Paper
2016-01-2125
Henry Hameister
This paper presents an approach to how existing production systems can benefit from Industry 4.0 driven concepts. This attempt is based on a communication gateway and a cloud-based system, that hosts all algorithms and models to calculate a prediction of the tool wear. As an example we will show the Refill Friction Stir Spot Welding (RFSSW), a solid state joining technique, which is examined at the Institute of Production Engineering (LaFT) of the Helmut-Schmidt-University, University of the Federal Armed Forces Hamburg, for years. RFSSW is a sub-section of friction welding, where a rotating tool that consists out of three parts is used to heat up material to a dough-like state. Since Refill Friction Stir Spot Welding produces a selective dot-shaped connection of overlapping materials, the production requirements are similar to riveting or resistance spot welding.
2016-09-27
Technical Paper
2016-01-2142
Pavel Lykov PhD, Artem Leyvi, Rustam M. Baytimerov, Aleksei Doikin, Evgeny Safonov
Abstract The treatment of solid surface by powerful streams of charged particles accelerated with power density ≥106 W/cm2 widely used for modification of different materials properties. The fast enter of electron beam power in the material of target causes the flow intense thermal and deformation processes. The changing of the structure, the phase composition, the microrelief of treated surface consequently happens. It is often accompanied by the hardening and increase of the wearing properties. The work proposed of using low-energy high-current electron beam as finish treatment of product obtained by selective laser melting of heat-resistant nickel alloy EP648. The subject of research was the surface properties of the product.
2016-09-20
Technical Paper
2016-01-1978
Philippe Coni, Sylvain Hourlier, Xavier Servantie, Laurent Laluque, Aude Gueguen
Abstract A 3D Stereoscopic Head-Up Display (HUD) using direct projection on a transparent screen is presented. Symbol incrustation in conformity with the landscape is performed through the use of simulated collimation offering a large eye-box, in excess of conventional HUD. The use of spectral glasses for our transparent screen was decided as most commonly used polarizing or active glasses were not adapted. Furthermore it gave ususeful green laser attack protection.
2016-09-20
Technical Paper
2016-01-1980
Syama M. Rao, Dineshkumar M
Abstract This paper studies admissible state trajectories for an unmanned aerial vehicle(UAV) by performing dynamic soaring technique in the wind gradient. An optimization problem is formulated by employing direct optimal piece wise control. A 3-DOF point mass model system dynamics of UAV is considered. The bank angle and lift co-efficient are identified as control variables. A UAV of mass 5.44kg is considered for this study. Performance measures considered are maximization of specific energy and maximization of specific energy rate extracted by the vehicle, and minimization of the control effort. The effects of linear and parabolic wind gradient on maximizing the specific energy of an autonomous dynamic soaring UAV is also studied and minimum linear gradient required is found. The loop radius of the loiter pattern is maximized for applications like surveillance and patrolling of a localized area along with energy maximization as objective function.
2016-09-20
Technical Paper
2016-01-1985
Fei Gao, Serhiy Bozhko, Patrick Wheeler
Abstract The paper will deal with the problem of establishing a desirable power sharing in multi-feed electric power system for future more-electric aircraft (MEA) platforms. The MEA is one of the major trends in modern aerospace engineering aiming for reduction of the overall aircraft weight, operation cost and environmental impact. Electrical systems are employed to replace existing hydraulic, pneumatic and mechanical loads. Hence the onboard installed electrical power increases significantly and this results in challenges in the design of electrical power systems (EPS). One of the key paradigms for future MEA EPS architectures assumes high-voltage dc distribution with multiple sources, possibly of different physical nature, feeding the same bus(es). In our study we investigate control approaches to guarantee that the total electric load is shared between the sources in a desirable manner. A novel communication channel based secondary control method is proposed in this paper.
2016-09-20
Technical Paper
2016-01-1986
Qian Li, Balakrishnan Devarajan, Xuning Zhang, Rolando Burgos, Dushan Boroyevich, Pradeep Raj
Abstract The more electric aircraft (MEA) concept has gained popularity in recent years. As the main building blocks of advanced aircraft power systems, multi-converter power electronic systems have advantages in reliability, efficiency and weight reduction. The pulsed power load has been increasingly adopted--especially in military applications--and has demonstrated highly nonlinear characteristics. Consequently, more design effort needs to be placed on power conversion units and energy storage systems dealing with this challenging mission profile: when the load is on, a large amount of power is fed from the power supply system, and this is followed by periods of low power consumption, during which time the energy storage devices get charged.
2016-09-20
Technical Paper
2016-01-1991
Syed J. Khalid
Abstract Aircraft subsystems essential for flight safety and airworthiness, including flight controls, environmental control system (ECS), anti-icing, electricity generation, and starting, require engine bleed and power extraction. Predictions of the resulting impacts on maximum altitude net thrust(>8%), range, and fuel burn, and quantification of turbofan performance sensitivities with compressor bleed, and with both high pressure(HP) rotor power extraction and low pressure(LP) rotor power extraction were obtained from simulation. These sensitivities indicated the judicious extraction options which would result in the least impact. The “No Bleed” system in Boeing 787 was a major step forward toward More Electric Aircraft (MEA) and analysis in this paper substantiates the claimed benefits.
2016-09-20
Technical Paper
2016-01-1994
Wei Wu, Yeong-Ren Lin, Louis Chow, Edmund Gyasi, John P. Kizito, Quinn Leland
Abstract For aircraft electromechanical actuator (EMA) cooling applications using forced air produced by axial fans, the main objective in fan design is to generate high static pressure head, high volumetric flow rate, and high efficiency over a wide operating range of rotational speed (1x∼3x) and ambient pressure (0.2∼1 atm). In this paper, a fan design based on a fan diameter of 86 mm, fan depth (thickness) of 25.4 mm, and hub diameter of 48 mm is presented. The blade setting angle and the chord lengths at the leading and trailing edges are varied in their suitable ranges to determine the optimal blade profiles. The fan static pressure head, volumetric flow rate, and flow velocity are calculated at various ambient pressures and rotational speeds. The optimal blade design in terms of maximum total-to-total pressure ratio and efficiency at the design point is obtained via CFD simulation.
2016-09-20
Technical Paper
2016-01-1997
Wei Wu, Yeong-Ren Lin, Louis Chow, Edmund Gyasi, John P. Kizito, Quinn Leland
Abstract The aircraft electromechanical actuator (EMA) cooling fan is a critical component because an EMA failure caused by overheating could lead to a catastrophic failure in aircraft. Fault tree analysis (FTA) is used to access the failure probability of EMA fans with the goal of improving their mean time to failure (MTTF) from ∼O(5×104) to ∼ O(2.5×109) hours without incurring heavy weight penalty and high cost. The dual-winding and dual-bearing approaches are analyzed and a contra rotating dual-fan design is proposed. Fan motors are assumed to be brushless direct current (BLDC) motors. To have a full understanding of fan reliability, all possible failure mechanisms and failure modes are taken into account.
2016-09-20
Technical Paper
2016-01-2012
Frank Feng, Debabrata Pal
Abstract There are many identical large solid-state switching Multi-Purpose Motor Controllers on board of one of the More Electric Aircrafts (MEA). The controllers drive over twice as many different machines with wide torque and speed ranges. The common motor controllers are installed in a central location. The machines are located at diverse and distant positions. Power is delivered and routed from the controllers to machines via a large network comprising of unshielded feeders and multiplexing units. The controllers are required to produce sine wave voltage output to machines, and draw clean power from the source to meet Power Quality (PQ) and Electromagnetic Interference (EMI) requirements. There are significant aircraft level weight savings with that concept. However, designing such a clean motor controller was a major power density challenge beyond switches, accounting for high torque main propulsion engine start and high speed Cabin Air Compressors.
2016-09-20
Technical Paper
2016-01-2014
Jonathan M. Rheaume, Charles Lents
Abstract Energy storage options for a hybrid electric commercial single aisle aircraft were investigated. The propulsion system features twin Geared Turbofan™ engines in which each low speed spool is assisted by a 2,500 HP electric motor during takeoff and climb. During cruise, the aircraft is powered solely by the turbine engines which are sized for efficient operation during this mission phase. A survey of state of the art energy storage options was conducted. Battery, super-capacitor, and flywheel metrics were collected from the literature including Specific Energy (Wh/kg), Volumetric Energy Density (Wh/L), Specific Power (W/kg), Cost ($/kWh), and Number of Cycles. Energy storage in fuels was also considered along with various converters sized to produce a targeted quantity of electric power. The fuel and converters include fuel cells (both proton exchange membrane and solid oxide operating on hydrogen or on jet fuel) and a turbogenerator (jet fuel or LNG).
2016-09-20
Technical Paper
2016-01-2029
Rolf Loewenherz, Francisco Gonzalez-Espin, Laura Albiol-Tendillo, Virgilio Valdivia-Guerrero, Ray Foley
Abstract This paper will present a multi-domain (electrical and thermal) model of a three phase voltage source converter and its implementation in Modelica language. An averaged model is utilised for the electrical domain, and a power balance method is used for linking the DC and AC sides. The thermal domain focuses in deriving the converter losses by deriving the analytical equations of the space vector modulation to derive a function for the duty cycle of each converter leg. With this, the conduction and switching losses are calculated for the individual switches and diodes, without having to model their actual switching behaviour. The model is very fast to simulate, as no switching events are needed, and allows obtaining the simulation of the electrical and thermal behaviour in the same simulation package..
2016-09-20
Technical Paper
2016-01-2027
Brett Robbins, Kevin J. Yost, Jon Zumberge
Abstract Detailed machine models are, and will continue to be, a critical component of both the design and validation processes for engineering future aircraft, which will undoubtedly continue to push the boundaries for the demand of electric power. This paper presents a survey of experimental testing procedures for typical synchronous machines that are applied to brushless synchronous machines with rotating rectifiers to characterize their operational impedances. The relevance and limitations of these procedures are discussed, which include steady-state drive stand tests, sudden short-circuit transient (SSC) tests, and standstill frequency response (SSFR) tests. Then, results captured in laboratory of the aforementioned tests are presented.
2016-09-20
Technical Paper
2016-01-2034
Tobias Kreitz, Frank Thielecke
Abstract The aviation industry is facing major challenges due to increased environmental requirements that are driven by economic constraints. For this reason, guidelines like "Flightpath 2050", the official guide of European aviation, call for significant reductions in pollutant emissions. The concept of the More Electric Aircraft offers promising perspectives to meet these demands. A key-enabler for this concept is the integration of new technologies on board of the next generation of civil transportation aircraft. Examples are electro-mechanical actuators for primary and secondary flight controls or the fuel cell technology as innovative electrical energy supply system. Due to the high complexity and interdisciplinarity, the development of such systems is an equally challenging and time-consuming process.
2016-09-20
Technical Paper
2016-01-2039
Prashant S. Vadgaonkar, Ullas Janardhan
Avionics industry is moving towards fly-by wire aircrafts with less reliance on mechanical systems leading to increase in the complexity of in-flight hardware elements. RTCA/DO-254 and EUROCAE ED-80 plays a vital role in the design assurance of airborne electronic hardware. RTCA/ DO-254 and EUROCAE ED-80 are the industry standards for Design Assurance Guidance for Airborne Electronic Hardware. The two different agencies FAA and EU regulate and apply this design assurance guidance to the regulatory law in CFR and EASA CS respectively. This paper discusses the need for DO-254 /ED-80 certification in Aerospace industry, the advantages and benefits to the avionics manufacturers. The paper presents the study made on similarities and differences between DO-254/ED-80.
2016-09-20
Technical Paper
2016-01-2050
Martin Espinosa Sanchez, Mario Pérez Millás
Abstract The effect of air pockets in capillaries in terms of pressure variations is investigated experimentally. Pressure sensors in aircraft are often installed separate to the pipes and connected with capillaries to minimise ignition sources within fuel tanks. Trapped air within these capillaries might distort the measurement. These effects are characterised in this paper. Extensive tests with different capillary configurations, trapped air volumes and pressure transients are studied. The data obtained shows that the main effect of trapped air during pressure transients is a delay in the pressure response against its excitation, causing local pressure oscillations around its source value until the pressure is equal in both places again. These oscillations can turn into high pressure peaks under critical conditions. Greater amounts of air can cause greater delays and viceversa.
2016-09-20
Technical Paper
2016-01-2044
Jeffrey J. Joyce, Scott Beecher, Laurent Fabre, Ramesh Rajagopalan
Abstract Over the past few decades, advanced methods have been developed for the analysis of digital systems using mathematical reasoning, i.e., formal logic. These methods are supported by sophisticated software tools that can be used to perform analysis far beyond what is practically achievable using “paper and pencil” analysis. In December 2011, RTCA published RTCA DO-178C [1] along with a set of technical supplements including RTCA DO-333 [2] which provides guidance on the use of formal methods towards the certification of airborne software. Such methods have the potential to reduce the cost of verification by using formal analysis instead of conventional test-based methods to produce a portion of the verification evidence required for certification.
2016-09-20
Technical Paper
2016-01-2052
Virgilio Valdivia-Guerrero, Ray Foley, Stefano Riverso, Parithi Govindaraju, Atiyah Elsheikh, Leonardo Mangeruca, Gilberto Burgio, Alberto Ferrari, Marcel Gottschall, Torsten Blochwitz, Serge Bloch, Danielle Taylor, Declan Hayes-McCoy, Andreas Himmler
Abstract This paper presents an overview of a project called “Modelling and Simulation Tools for Systems Integration on Aircraft (MISSION)”. This is a collaborative project being developed under the European Union Clean Sky 2 Program, a public-private partnership bringing together aeronautics industrial leaders and public research organizations based in Europe. The provision of integrated modeling, simulation, and optimization tools to effectively support all stages of aircraft design remains a critical challenge in the Aerospace industry. In particular the high level of system integration that is characteristic of new aircraft designs is dramatically increasing the complexity of both design and verification. Simultaneously, the multi-physics interactions between structural, electrical, thermal, and hydraulic components have become more significant as the systems become increasingly interconnected.
2016-09-20
Technical Paper
2016-01-2059
Rolf Loewenherz, Virgilio Valdivia-Guerrero, Daniel Diaz Lopez, Joshua Parkin
Abstract Auto transformer rectifier units (ATRUs) are commonly used in aircraft applications such as electric actuation for harmonic mitigation due to their high reliability and relative low cost. However, those components and the magnetic filter components associated to it are the major contributors to the overall size and weight of the system. Optimization of the magnetic components is essential in order to minimize weight and size, which are major market drivers in aerospace industry today. This requires knowledge of the harmonic content of the current. This can be obtained by simulation, but the process is slow. In order to enable fast and efficient design space exploration of optimal solutions, an algebraic calculation process is proposed in this paper for multi-pulse ATRUs (e.g. 12-pulse and 18-pulse rectifiers), starting from existing solution proposed for 6 pulse rectifier in the literature.
2016-09-20
Technical Paper
2016-01-2058
Thibaut Billard, Cedric Abadie, Bouazza Taghia
Abstract The present paper reports non-electrically intrusive partial discharge investigations on an aeronautic motor. Relevancy, robustness and repeatability of partial discharge testing procedures, both on insulating materials characterization and on operating aeronautic equipment are essential to ensure reliability of the aircraft systems. The aim of this paper is to be the very first step of defining such procedures and the associated test equipment. To do so, the paper will start by providing an understanding of partial discharge phenomena and will review typical more electrical aircraft architecture. Key characteristics causing partial discharge risk to increase will be highlighted. The impact of harness length, high performance power electronics and voltage level increase on insulation system is demonstrated.
2016-09-20
Technical Paper
2016-01-2069
Zied Aloui, Nawfal Ahamada, Julien Denoulet, Martin Rayrole, Francine Pierre, Marc Gatti
Abstract Avionics is one kind of domain where prevention prevails. Nonetheless failures occur, sometimes due to pilot misreacting, flooded in information. Sometimes information itself would be better verified than trusted. To avoid some kind of failure, it has been thought to add,in midst of the ARINC664 aircraft data network, a new kind of monitoring.
Viewing 1 to 30 of 3428