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Journal Article

ℒ1 Adaptive Flutter Suppression Control Strategy for Highly Flexible Structure

2013-09-17
2013-01-2263
The aim of this work is to apply an innovative adaptive ℒ1 techniques to control flutter phenomena affecting highly flexible wings and to evaluate the efficiency of this control algorithm and architecture by performing the following tasks: i) adaptation and analysis of an existing simplified nonlinear plunging/pitching 2D aeroelastic model accounting for structural nonlinearities and a quasi-steady aerodynamics capable of describing flutter and post-flutter limit cycle oscillations, ii) implement the ℒ1 adaptive control on the developed aeroelastic system to perform initial control testing and evaluate the sensitivity to system parameters, and iii) perform model validation and calibration by comparing the performance of the proposed control strategy with an adaptive back-stepping algorithm. The effectiveness and robustness of the ℒ1 adaptive control in flutter and post-flutter suppression is demonstrated.
Technical Paper

“Symbiose”: Technology Developments for Bioregeneration in Space

1994-06-01
941348
Dedicated technology has been developed to support long-term biological experiments on-board spacecraft. These developments include a microgravity compatible tubular photo bioreactor for the cultivation of micro algae at very high biomass concentrations and with very high gas exchange rates, a microgravity compatible gas / liquid phase separator which also works as a pneumatic low shear-stress pump, a microgravity compatible dehumidifier, and a maltose separating reverse osmosis unit. Integration of these technologies into a partially closed artificial ecosystem form the foundation of the SYMBIOSE concept (System for Microgravity Bioregenerative Support of Experiments).
Technical Paper

“Smart Panel” Electronic Circuit Breaker Control Technology

2008-11-11
2008-01-2880
This paper will discuss using Astronics “Smart Panel” illuminated control panels to control an electronic power distribution system. A discussion of wiring simplification, automatic control possibilities and real time load monitoring is presented. The challenges of retrofitting the system into older aircraft will be covered as well. The paper also explains Electronic Circuit Breaker technology, arc fault protection, panel lighting technologies, control bus options, displays, and human input technology (buttons and knobs).
Technical Paper

“Model Based Predictive Control of MELISSA Photobioreactors. Steady State Determination”

1994-06-01
941411
Mathematical modeling and control of artificial ecosystems, such as MELISSA, require first the study of physical and biological characteristics in optimal and limiting conditions. Following the previous determination of the stoichiometric equations (Spirulina compartment) and regarding the two phototrophic compartments of MELISSA (Rhodospirillaceae and Spirulina), we have first to focus our control study on the growth kinetics for the light source. In this paper, we recall the theoretical equations of microbial growth kinetics and emphasise the problem of the light transfer in a photobioreactor. We present their adaptations to our pilot plant taking into account technological and biological specifics (lamp spectrum, working illuminated volume, growth rate,…). We then develop the principles and structure of the control system and describe tests of both the hardware and software for several steady state configurations.
Technical Paper

“Greater Than the Sum of its Parts” Integrated Flight Training/Aircrew Coordination

1994-10-01
942132
The requirement for crew resource management (CRM), or aircrew coordination training (ACT) in military parlance, has been well documented and attested to. In addition, aircraft systems training has become more intense and more in-depth in the new aircraft designs, especially in multi-crew and complex aircraft such as the MV-22 Osprey Tiltrotor. (see Figure 1) Former training systems detailed training procedures that called for classroom training and simulation/simulator training followed by flight training. Improvements in aircraft flight skills training provide increased flying training capability coupled with reduced training time by integrating a mixed simulation/flight training syllabus, e.g. two to three simulation periods followed by one or two flight training periods covering the same material/skills. In addition, the simulation training will introduce new skills; the following flight periods will further refine/hone those skills.
Technical Paper

“Fuel Flow Method2” for Estimating Aircraft Emissions

2006-08-30
2006-01-1987
In recent years there has been increasing interest in quantifying the emissions from aircraft in order to generate inventories of emissions for climate models, technology and scenario studies, and inventories of emissions for airline fleets typically presented in environmental reports. The preferred method for calculating aircraft engine emissions of NOx, HC, and CO is the proprietary “P3T3” method. This method relies on proprietary airplane and engine performance models along with proprietary engine emissions characterizations. In response and in order to provide a transparent method for calculating aircraft engine emissions non proprietary fuel flow based methods 1,2,3 have been developed. This paper presents derivation, updates, and clarifications of the fuel flow method methodology known as “Fuel Flow Method 2”.
Technical Paper

“Flexible” Cargo Handling Systems for Standard-Body Airplanes

1986-09-01
861153
The manner in which the lower deck cargo compartments of standard-body airplanes are designed, equipped, and serviced has not changed appreciably over the past 50 years. A number of factors now at work within the air transportation industry are causing carriers and airplane manufacturers to explore alternative approaches to these tasks. This paper reviews these factors, presents a new approach to lower deck cargo handling systems design, and describes how this approach can be applied to standard-body airplanes.
Technical Paper

“Condensation – Why it Needs to be Addressed in Every Aircraft”

2003-09-08
2003-01-3000
A wide body aircraft carries almost a half–ton of water and ice between the cabin and skin of the aircraft. The water can get on wires and connectors, which can cause electrical problems, cause corrosion and rust, and, eventually, “rain in the plane”. The speaker is the CEO of CTT Systems that has developed a system that solves the condensation by using dry air. The speaker will discuss how condensation can be prevented and how airlines can also save maintenance costs in the process. This topic is relevant for the attendees at the Aerospace Expo, as they are decision makers who need to be aware of this issue. It is also important for the MRO shows as the attendees are on the front lines of dealing with this problem.
Technical Paper

“A Dry Aircraft is a Safer Aircraft – Beating Condensation by Using Dry Air”

2003-09-08
2003-01-3017
The airline industry seems to be providing more leisure features on planes like inflight entertainment, Internet access and Digital TV, but it seems the airline industry has ignored the issue of excess condensation on aircraft, which had plagued carriers since the birth of the airline industry. How safe are passengers when a wide body aircraft carries in excess almost a half ton of water and ice between the cabin and skin of the aircraft? Besides the added weight straining the aircraft, excess condensation soaks wires and connectors which can cause electrical shorts. There have been instances of emergency doors frozen shut, locked by ice stemming from excess water dripping inside the plane. Extra water also causes “rain-in-the-plane”, an issue that has gained national attention and causes passenger discomfort. It's time for the industry to address what has become a serious issue.
Technical Paper

‘Issues and Behaviors of Airborne Particulate Matters under Microgravity Environment’

2004-07-19
2004-01-2328
During several ISS missions, there were false alarms at both US and Russian smoke detectors. High local airborne particulate concentrations and interior deposits are considered the causes for such anomalies. Alternatives are proposed to replace or complement these faulty smoke detectors. The entrained zeolite particles may play a role in causing problems with check valves and air save pumps in CDRA and Vozdukh. Another incidence has been the dispersion of particulates out of Metox regeneration oven. Particulate matters with aerodynamic diameter of 15 microns and above, which normally settle down on earth, stay airborne under micro-gravity and thereby cause the above-mentioned nuisances. The motion of such a particle along a gas stream with an initial velocity can be expressed by theoretical equations. Stokes' Law leads to the descriptions of inertial precipitation of aerosols that are important in solving the issues.
Technical Paper

‘Bigelow Aerospace® Life Support Laboratory - Planning and Status’

2004-07-19
2004-01-2474
This Life Support Laboratory consists of a simulator of the spacecraft called Nautilus, which houses Air Revitalization Subsystem, Atmospheric Control and Supply, and Fire Detection and Suppression in the Equipment Area. There are supporting facilities including a Human Metabolic Simulator, simulated Low and Moderate Temperature Coolant Loop, chemical analysis bench, purified water supply, vacuum and gas supplies. These facilities are scheduled to be completed and start to operate for demonstration purposes by March 2005. There are an ARES Ground Model (AGM) and a Trace Contaminant Control Assembly in the ARS. The latter will be integrated with the AGM and a Condensing Heat Exchanger. The unit of AGM is being engineered, built, and will be delivered in early 2005 by EADS Space Division. These assemblies will be operated for sensitivity analysis, integration and optimization studies. The main goal is the achievement for optimal recovery of oxygen.
Technical Paper

srv-k Status Aboard the International Space Station During Missions 15 and 16

2008-06-29
2008-01-2191
The paper summarizes the experience gained on the ISS water management system during the missions of ISS-1 through ISS-16 (since November 2 2000, through December 31, 2007). The water supply sources and structure, consumption and supply balance at various phases of space station operation are reviewed. The performance data of the system for water recovery from humidity condensate SRV-K and urine feed and pretreatment system SPK-U in the Russian orbital segment are presented. The key role of water recovery on a board the ISS and the need to supplement the station's water supply hardware with a system for water reclamation from urine, water from a carbon dioxide reduction system and hygiene water is shown.
Technical Paper

prediction in new Metal Joining Processes

1960-01-01
600020
NEW WELDING processes are dropping costs while providing improvements in weld quality. This paper describes some of the more promising new developments in pressure and fusion welding and brazing. Included in the discussion are ultrasonic, high frequency resistance, foil seam, magnetic force, percussion, friction, and thermopressure welding and diffusion bonding. The description of adhesive bonding includes the development of glass or ceramic materials as structural adhesives.*
Technical Paper

euces Software Development

2008-06-29
2008-01-2072
The euces project was initiated to be prepared for the future role of EADS as stage system prime for stage and launcher developments. Launcher stages for NGLV need to meet ambitious mission and operational demands. The paper will present a brief overview of the currently existing COMPONENT libraries and its possibilities as well as an application example which will be a simplified functional model of the ARIANE 5 EPS upper stage w.r.t. physical model formulation of its incorporated components, its schematic, data initialisation and simulation results obtained. The simulation results will be compared to flight data of a dedicated flight.
Technical Paper

considerations of some JET-DEFLECTION PRINCIPLES for - - directional control - - lift

1958-01-01
580062
THE performance characteristics of various devices applicable for jet directional control, lift augmentation, and VTOL-STOL studied at the NACA Lewis Laboratory are discussed, including jet deflection devices applicable to the conventonal round nozzle and novel nozzle configurations. The results indicate that many of the deflection devices applicable to conventional nozzles can readily be used for directional control or lift augmentation. Other deflection devices, such as movable plug, internal flap, cylindrical thrust reverser, swiveled primary with fixed shroud, and 90 deg side-bleed nozzle, are limited in application to jet directional control or aircraft trim because the loss in axial thrust for a given deflection force is prohibitive or the maximum deflected force obtainable is limited.
Technical Paper

Zoonoses and Enclosed Environments

1991-07-01
911513
The likelihood of transmission of potential disease agents between animals and man during spaceflight is a real concern. Development of disease exclusion lists for animals and refinement of animal containment units have been the principal means of providing protection to the crew members. Awareness of potential latent infections and a judicious use of the higher risk category of animals such as wild-caught nonhuman primates provides another level of protection. Use of high efficiency filters, gasketing, and differential air pressures have all enabled increasing levels of safety through containment of potential aerosol escape from animal habitats.
Technical Paper

Zone of Influence of Porous Suction Tubes in Condensing Heat Exchanger for Space Systems

2008-06-29
2008-01-2075
A “next generation” condensing heat exchanger for space systems has to satisfy demanding operational requirements under variable thermal and moisture loads and reduced gravity conditions. Mathematical models described here are used to investigate transient behavior of wetting and de-wetting dynamics in the binary porous system of porous tubes and porous cold plate. The model is based on the Richard's equation simplified for the zero-gravity conditions. The half-saturation distance or the zone of influence of the porous annular suction tubes on the cold-plate porous material will be in the range of 1 to 10 cm for the time scales ranging from 100 to 10,000 seconds and moisture diffusivity in the range of D = 10-4 to 10-6 m2/s.
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