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High Accuracy Articulated Robots with CNC Control Systems

SAE International Journal of Aerospace

Electroimpact Inc.-Bradley Saund, Russell DeVlieg
  • Journal Article
  • 2013-01-2292
Published 2013-09-17 by SAE International in United States
A robotic arm manipulator is often an appealing method to position drills, bolt inserters, automated fiber placement heads, or other end effectors. In a standard robot the flexibility of the cantilevered arm as well as backlash in the drive system lead to large positioning errors. Previous work has greatly reduced this error through the use of secondary scales and a mathematical model of the robot deflection running on a CNC controller. Further research improved upon this model by accounting for linear deformation of each robot link regardless of position. The parameters describing these deformations are determined through a calibration routine and then used in real time to guide the end effector accurately to any reachable pose. In practice this method has been used to achieve total on-part positioning accuracy of better than +/− 0.25mm.
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Considerations on the Use of Hydrophobic, Superhydrophobic or Icephobic Coatings as a Part of the Aircraft Ice Protection System

Bombardier Aerospace-Guy Fortin
Published 2013-09-17 by SAE International in United States
Ice adhesion on critical aircraft surfaces is a serious potential hazard that runs the risk of causing accidents. For this reason aircraft are equipped with active ice protection systems (AIPS). AIPS increase fuel consumption and add complexity to the aircraft systems. Reducing energy consumption of the AIPS or replacing the AIPS by a Passive Ice Protection System (PIPS), could significantly reduce aircraft fuel consumption. New coatings with superhydrophobic properties have been developed to reduce water adherence to surfaces. Superhydrophobic coatings can also reduce ice adhesion on surfaces and are used as icephobic coatings.The question is whether superhydrophobic or icephobic coatings would be able to reduce the cost associated with AIPS. To address this concern, this paper reviews the current knowledge on superhydrophobic and icephobic coatings, proposes a parameter to quantify the coating hydrophobicity level and presents methods to adapt available experimental data to aircraft applications.A second important question is whether the durability of superhydrophobic coatings is adequate for aircraft applications. Most of the available coatings that can reduce AIPS power consumption show poor erosion resistance…
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Aerodynamic Characteristics Study and Possible Improvements of MAAT Feeder Airships

Don State Technical University-Rudolf Neydorf, Anna Boldyreva
University of Hertfordshire-Vitaly Voloshin, Yong Chen
Published 2013-09-17 by SAE International in United States
This paper is dedicated to the study and improvement of the aerodynamic properties of the feeder airship in the context of MAAT project. FP7 MAAT project is based on the concept of two different types of airships (the cruiser and the feeder) working together as a transportation system. The current feeder concept includes unconventional shape changing envelope. Two problems are considered in this paper.The first problem is to find a condition of the effective vertical ascent for the feeder (from the ground to the altitude of the cruiser). A series of CFD simulations were carried out for the top flow for a range of altitudes from 0 to 16 km and velocities between 2 and 10 m/s. The results confirm the appearance of some negative effects, including high drag during the vertical ascent, especially, at low altitudes.The second problem is to study and reduce the side wind effects on the ascending feeder airship. Another series of CFD simulations was conducted for the side flow at the same altitudes as in the first problem and for…
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A Non-Destructive Method to Classify the Correct Installation of Blind Bolts

SAE International Journal of Materials and Manufacturing

Airbus Military-Juan Ramon Astorga
Airbus Operations S.L.-Desire Guzman
  • Journal Article
  • 2013-01-2184
Published 2013-09-17 by SAE International in United States
Aerospace manufacturing requires efficient manufacturing processes. Composite materials are extensively used and manufacturing processes must evolve to overcome composite constraints for manufacturing and joining. Bolting is an extended joining process for composite materials in which a deformable blind bolt is stressed until joining forces are high enough to cause bolt breakage and ensure sufficient compression forces in the joint.Among bolting methods, blind bolting is an efficient composite joining method that enables the construction of aerospace composite structures accessing joints from a single side of the joint (front side), thus allowing for constructing closed structures where accessing the back side (blind side) is not possible. However, not being able to access the deformed head at the blind side prevents to perform a quality control and ensure a proper bolt deformation and a proper installation.In this research work a nondestructive method for blind bolt installation is developed. Several potential inspection techniques (shearography, thermography, frequency response methods and ultrasonic methods) are tested for blind bolting inspection suitability assessment. An ultrasonic measurement technique is identified as partially capable of…
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Multi-Layer Insulation Fabrication and Resistance on Blanket Surface

AR TECH-Amir Massoudi
Published 2013-09-17 by SAE International in United States
Multi-Layer Insulation (MLI) is the thermal insulation typically used in spacecraft or any other devices that are exposed to both extreme heat and cold. MLI blankets work to protect delicate internal and external applications from UV radiation, atomic oxygen, and mechanical stresses by using Teflon coated fiberglass cloth. The layers are usually made of a film made out of polyester or polyimide with vapor deposited layers of aluminum on one or both sides of the film to form reflector layers. These reflectors are separated by materials with low thermal conductivity. All the layers simply protect the system by preventing excessive heat loss from inner components and excessive heating from outer sources.Typically, MLI blankets are divided into a cover or outer layer, a reflector, a separator layer, an inner layer, and it has hardware installed to pass electrical charge from the surface of the blanket. As the roles of each layer differ, materials that fit the role are used to fabricate specific layers.In this paper we will discuss an issue of passing conductivity on blankets, passing…
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Integrated Reconfigurable Aero-Propulsion (IRAP) Control for Improved Fault Tolerance

Scientific Systems Company Inc.-Jovan D. Boskovic, Joseph Jackson, Raman Mehra
Published 2013-09-17 by SAE International in United States
In this paper we present results of a study of an integrated aero-propulsion flight control system. The resulting problem is that of controlling the system in which actuators operate on different time scales. This is a difficult problem since the control strategy needs to balance between not using the slow actuator at all, and slowing down the overall system to the time scale of the slow actuator. In the case of aero-propulsion control design for F/A-18 aircraft, the part of the control derivative matrix associated with engines is not full rank so not all states of interest can be simultaneously forced to track the commands. A control strategy that takes this constraint into account has been developed. The proposed IRAP approach is illustrated through simulation of F/A-18 aircraft dynamics under flight-critical control effector failures.
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More Electric Architecture for Engine and Aircraft Fuel System

IHI Aerospace Co., Ltd.-Hitoshi Oyori
IHI Corporation-Noriko Morioka
Published 2013-09-17 by SAE International in United States
The authors are currently developing the MEE (More Electric Engine) electric motor-driven fuel pump system for aircraft engines. The electric fuel system will contribute to the reduction of engine power extraction to drive the fuel pump; thus, an improvement in engine efficiency will be expected. In addition, the engine system reliability will be improved by introducing advanced electric architecture, and the reduction of hydraulic components, fuel tubes and fittings is effective to enhance the maintainability of the engine.Although it is considered that the MEE electric fuel system will realize several benefits, there are technical challenges to introduce such new electric system into aircraft. One of the key technical challenges is to construct a redundant and simplified electric fuel system, because continuous operation of the fuel pump system is crucial for aircraft safety. The authors consider that integration of the aircraft fuel system and engine fuel system will provide a solution for the technical issue, and propose a concept of an integrated electric fuel system in this paper.
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Integrated Hole and Countersink Inspection of Aircraft Components

Electroimpact Inc.-Joshua Smith, Duncan Kochhar-Lindgren
Published 2013-09-17 by SAE International in United States
Precision hole inspection is often required for automated aircraft assembly. Direct contact measurement has been proven reliable and accurate for over 20 years in production applications. At the core of the hole measurement process tool are high precision optical encoders for measurement of diameter and countersink depth. Mechanical contact within the hole is via standard 2-point split ball tips, and diametric data is collected rapidly and continuously enabling the system to profile the inner surface at 0 and 90 degrees. Hole profile, countersink depth, and grip length data are collected in 6 seconds. Parallel to the active process, auto-calibration is performed to minimize environmental factors such as thermal expansion. Tip assemblies are selected and changed automatically. Optional features include concave countersink and panel position measurement.
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Rivet and Bolt Injector with Bomb Bay Ejection Doors

SAE International Journal of Aerospace

Electroimpact Inc.-Cosmos Krejci
  • Journal Article
  • 2013-01-2151
Published 2013-09-17 by SAE International in United States
Electroimpact's newest riveting machine features a track-style injector with Bomb Bay Ejection Doors. The Bomb Bay Ejection Doors are a robust way to eject fasteners from track style injector. Track style injectors are commonly used by Electroimpact and others in the industry. Using the Bomb Bay Doors for fastener ejection consists of opening the tracks allowing very solid clearing of an injector when ejecting a fastener translating to a more reliable fastener delivery system. Examples of when fastener ejection is needed are when a fastener is sent backwards, when there are two in the tube, or when a machine operator stops or resets the machine during a fastening cycle. This method allows fasteners to be cleared in nearly every situation when ejecting a fastener is required. Additional feature of Electroimpact's new injection system is integrated anvil tool change. Anvils with fingers are parked on each Injector and an indexing system automatically changes tools for different fastener diameter. Fundamentally, this track-style Injector has only one moving part, the Pusher, used in every fastening cycle. With the…
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Integration Issues for Vehicle Level Distributed Diagnostic Reasoners

Cranfield University-Faisal Khan, Tarapong Sreenuch
IVHM Centre Cranfield University-Ian Jennions
Published 2013-09-17 by SAE International in United States
In today's aircraft the diagnostic and prognostic systems play a crucial part in aircraft safety while reducing the operating and maintenance costs. Aircraft are very complex in their design and require consistent monitoring of systems to establish the overall vehicle health status. Most diagnostic systems utilize advanced algorithms (e.g. Bayesian belief networks or neural networks) which usually operate at system or sub-system level. The sub-system reasoners collect the input from components and sensors to process the data and provide the diagnostic/detection results to the flight advisory unit. Several sources of information must be taken into account when assessing the vehicle health, to accurately identify the health state in real time. These sources of information are independent system-level diagnostics that do not exchange any information/data with the surrounding systems. This limits the system by preventing cross check or health status information exchange amongst the related sub-systems. This article discusses the issues related to the integration of a vehicle level diagnostic reasoner to sub-system level reasoners and information exchange between the sub-system reasoners and the vehicle level…
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