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Investigation of Tradeoffs between Efficiency, Mass, Cost, Service Factor, and Power Factor in Induction Machines

SAE International Journal of Aerospace

Purdue Univ.-Scott Sudhoff, Steven Pekarek
Purdue Univ. - ECE-Nir Vaks
  • Journal Article
  • 2010-01-1785
Published 2010-11-02 by SAE International in United States
The focus of this research is to perform a detailed investigation of the tradeoffs between mass, efficiency, service factor (SF), power factor (PF), and cost of commercially available induction machines (IMs). To support this effort, data from a large number of IMs is used to establish Pareto-optimal fronts between these competing objectives. From the Pareto-optimal fronts, relatively straightforward models are formulated for the mass versus loss, cost versus loss, SF versus mass, PF versus cost. Parameters of the models are obtained using a genetic algorithm (GA).
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SoH Recognition of Aviation Batteries Via Passive Diagnostic Device

SAE International Journal of Aerospace

GEM Power, LLC-John E. James, Boris Tsenter
  • Journal Article
  • 2010-01-1762
Published 2010-11-02 by SAE International in United States
Aviation battery maintenance is trending toward on-condition maintenance. Nickel-Cadmium (NiCd), Valve Regulated Lead-Acid (VRLA), or prospective Li-ion batteries are used to start engines, provide emergency back-up power, and assure ground power capability for maintenance and pre-flight checkout. As these functions are mission essential, State of Health (SoH) recognition is critical. SoH includes information regarding battery energy, power and residual cycle life. This paper describes an SoH recognition technique for on-board aviation batteries and presents a passive diagnostic device (PDD). The PDD monitors on-board system battery current, voltage and ambient temperature and utilizes no active signals to the battery which can be restricted or even prohibited in order to avoid any interference with the vehicle electrical system. A procedure for sampling, treatment and analysis of transient and stationary battery voltage and current under changeable thermal condition resulting in a matrix of battery parameters is discussed. A matrix of parameters (MoP) like ohm and chemical resistance, instantaneous and dynamic open circuit voltage forms the basis for SoH recognition.
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A Framework for Developing an EPS Health Management System

SAE International Journal of Aerospace

Boeing Research & Technology-Charles Morris, Kirby Keller
Global Strategic Solutions LLC-Luis Hernandez, Michael Mullins
  • Journal Article
  • 2010-01-1725
Published 2010-11-02 by SAE International in United States
This paper describes a framework for developing an Integrated Electrical Power System (EPS) Health Management System. The framework is based on the perspective that health management, unlike other capabilities, is not a self-contained, stand-alone system, but is rather an integral part of every aircraft subsystem, system, and the entire platform. Ultimately, the objective is to improve the entire maintenance, logistics and fleet operations support processes. This perspective requires a new mindset when applying systems engineering design principles. The paper provides an overview description of the framework, the potential benefits of the approach and some critical design and implementation issues based on current development efforts.
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A Hybrid Economy Bleed, Electric Drive Adaptive Power and Thermal Management System for More Electric Aircraft

SAE International Journal of Aerospace

Northrop Grumman Corp.-Clarence Lui, Paramjit Walia
PC Krause & Associates-Tim C. O'Connell
  • Journal Article
  • 2010-01-1786
Published 2010-11-02 by SAE International in United States
Minimizing energy use on more electric aircraft (MEA) requires examining in detail the important decision of whether and when to use engine bleed air, ram air, electric, hydraulic, or other sources of power. Further, due to the large variance in mission segments, it is unlikely that a single energy source is the most efficient over an entire mission. Thus, hybrid combinations of sources must be considered.An important system in an advanced MEA is the adaptive power and thermal management system (APTMS), which is designed to provide main engine start, auxiliary and emergency power, and vehicle thermal management including environmental cooling. Additionally, peak and regenerative power management capabilities can be achieved with appropriate control. The APTMS is intended to be adaptive, adjusting its operation in order to serve its function in the most efficient and least costly way to the aircraft as a whole.This paper presents a hybrid APTMS, which balances the use of economy bleed air and electric drive in a single architecture that automatically adapts to changing aircraft conditions to optimally regulate its function.…
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Model Based Diagnostics of an Aircraft Generator Using AAKR and SPRT

SAE International Journal of Aerospace

Global Strategic Solutions, LLC-Karthik Kappaganthu, Yuan Li, Luis Hernandez
  • Journal Article
  • 2010-01-1761
Published 2010-11-02 by SAE International in United States
Electrical power generation is an important component in the Electrical Power System of an Aircraft (EPS). In this paper we present a model based diagnostic framework for early generator degradation detection and tracking within an Aircraft Generator. The nominal health state is modeled empirically using an Auto-associative Kernel Regression (AAKR) technique using signals extracted from a healthy generator. Later the health state is estimated by comparing sensor observations with the model predictions. Finally, a Sequential Probability Ratio Test (SPRT) is used to detect and track degradation. This model based framework showed excellent degradation tracking performance when it was tested on a unit that was run to failure.
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Fabrication of Titanium Aerospace Hardware using Elevated Temperature Forming Processes

SAE International Journal of Aerospace

Boeing Co.-Larry Hefti
  • Journal Article
  • 2010-01-1834
Published 2010-09-28 by SAE International in United States
Titanium is a difficult material to fabricate into complex configurations. There is several elevated temperature forming processes available to produce titanium components for aerospace applications. The processes to be discussed are Superplastic Forming (SPF), hot forming and creep forming. SPF uses a tool that contains the required configuration and seals around the periphery so inert gas pressure can be used to form the material. Of the processes to be discussed, this is the one that can produce the most complex shapes containing the tightest radii. A variation of the process combines an SPF operation with diffusion bonding (SPF/DB) of two or more pieces of titanium together to produce integrally stiffened structure containing very few fasteners. Another process for shaping titanium is hot forming. In this process, matched metal tools, offset by the thickness of the starting material, are used to form the part contour at elevated temperature. The required part geometry usually contains no sharp features that have to be formed. Starting blanks are often preformed in order to get the material as close as…
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Applied Accurate Robotic Drilling for Aircraft Fuselage

SAE International Journal of Aerospace

Electroimpact Inc.-Russell Devlieg
Northrop Grumman Corp.-Todd Szallay
  • Journal Article
  • 2010-01-1836
Published 2010-09-28 by SAE International in United States
Once limited by insufficient accuracy, the off-the-shelf industrial robot has been enhanced via the integration of secondary encoders at the output of each of its axes. This in turn with a solid mechanical platform and enhanced kinematic model enable on-part accuracies of less than +/−0.25mm. Continued development of this enabling technology has been demonstrated on representative surfaces of an aircraft fuselage. Positional accuracy and process capability was validated in multiple orientations both in upper surface (spindle down) and lower surface (spindle up) configurations. A second opposing accurate robotic drilling system and full-scale fuselage mockup were integrated to simulate doubled throughput and to demonstrate the feasibility of maintaining high on-part accuracy with a dual spindle cell.
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Production Implementation of Multiple Machine, High Speed Fiber Placement for Large Structures

SAE International Journal of Aerospace

Electroimpact Inc.-Todd Rudberg, Rob Flynn, Justin Nielson
  • Journal Article
  • 2010-01-1877
Published 2010-09-28 by SAE International in United States
A two machine Automated Fiber Placement (AFP) cell capable of laying 1/2\mi and 1/4\mi tow at rates up to 1800\mi/min (45.7 m/min), including feeds and cuts, has been implemented for the manufacture of large primary aircraft structures.The control architecture of the cell is such that part programs are machine independent and can run on either machine or simultaneously on both machines at the same time. A Central Cell Controller pushes part programs to each AFP machine and coordinates the cell.Volumetric accuracy of the two machines is under 0.008\mi (0.2 mm) radial error in the entire compensated envelop, which is approximately 64' x 21' x 14' (19.5 m x 6.4 m x 4.3 m) for each machine. This is accomplished through optimization of volumetric kinematic compensation parameters using a linear numerical solver. The machines reference a common coordinate system which allows great flexibility in part programming.A detachable head design was implemented which allows each machine to swap between 1/4\mi and 1/2\mi tow widths in 120 seconds. The creel is contained on the head which provides very…
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Expanding the Use of Robotics in Airframe Assembly Via Accurate Robot Technology

SAE International Journal of Aerospace

Electroimpact Inc.-Russell Devlieg
  • Journal Article
  • 2010-01-1846
Published 2010-09-28 by SAE International in United States
Serial link articulated robots applied in aerospace assembly have largely been limited in scope by deficiencies in positional accuracy. The majority of aerospace applications require tolerances of +/−0.25mm or less which have historically been far beyond reach of the conventional off-the-shelf robot. The recent development of the accurate robot technology represents a paradigm shift for the use of articulated robotics in airframe assembly. With the addition of secondary feedback, high-order kinematic model, and a fully integrated conventional CNC control, robotic technology can now compete on a performance level with customized high precision motion platforms. As a result, the articulated arm can be applied to a much broader range of assembly applications that were once limited to custom machines, including one-up assembly, two-sided drilling and fastening, material removal, and automated fiber placement.
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The Effects of Surface Texture on Fretting Fatigue between Fastener and Aluminum Structure

SAE International Journal of Aerospace

Alcoa Fastening Systems-Hasim Mulazimoglu
  • Journal Article
  • 2010-01-1854
Published 2010-09-28 by SAE International in United States
Multi-fastener lap joints are vulnerable to fretting fatigue when they are subjected to repeated loading. In general the fretting fatigue condition leads to degraded properties of metallic structures due to the presence of the surface stress concentration resulting at the sites of fretting pits. In many cases, fretting can result in premature structure failures therefore a series of counter measures are frequently taken to minimize fretting especially at the fastener holes. One of major factors that affect the fretting phenomena between the fastener and fastener hole is the surface condition of the fasteners.In this study, the influences of the surface texture and the surface plating of the fastener on the joint life were investigated by conducting double lap shear fatigue testing. It has been found that the joint fretting fatigue resistance is very sensitive to the surface texture of the fastener and as the surface roughness of the fastener is reduced the joint life increases. In addition, the test results presented in this paper indicated that the use of copper plating substantially improves the joint…
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