| Analysis and Experimentation of Control Strategies for Underactuated Spacecraft |
Sep-2009 |
180 pages |
| Authors:
Jason S Hall; MAN MACHINE SYSTEMS INC ARLINGTON VA
|
 | A laboratory spacecraft simulator testbed is first introduced to examine the problem of multiple spacecraft interacting in close proximity. This testbed enables validation of guidance, navigation and control (GNC) algorithms by combining 6-Degrees of Freedom (DoF) computer simulation with 3-DoF Hardware-In-the-Loop (HIL) experimentation. The presented 3-DoF spacecraft simulator employs a novel control actuator configuration consisting of a Miniature Single Gimbaled Control Moment Gyroscope (MSGCMG) and dual on/off cold-gas in-plane vectorable ... |
|
| Stochastic Load Transfer Model for Fastened Joints |
Feb-2009 |
71 pages |
| Authors:
Adam K Parks; Jorge Abanto-Bueno; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIRECTORATE
|
| In the investigation presented in this document, the capabilities and limitations of two well-know full-field techniques, namely the digital image correlation (DIC) and the thermoelastic stress analysis (TSA), are assessed. The main goals of this project are to assess the limitations of the two experimental techniques, determine if either technique can detect differences in the strain field of varying clamping loads, and subsequently compare the experimental results to a finite ... |
|
| Quenching Dynamics of Electronically Excited Hydroxyl Radicals |
19 MAY 2008 |
6 pages |
| Authors:
Marsha I. Lester; PENNSYLVANIA UNIV PHILADELPHIA
|
| Collisional quenching of electronically excited OH radicals by molecular partners has been investigated over the past 25 years, principally by evaluating the quenching cross sections for partners of aeronautical, atmospheric, and/or combustion relevance. Yet little is known about the outcome of these electronic quenching events, except that they facilitate the efficient removal of OH from the excited Alpha 2sigma+ electronic state by introducing nonradiative decay pathways. Most recently, we carried ... |
|
| Mixed-Flow Waterjet (MxWJ) Model 5662-1: Initial Study of Yaw Effects on Waterjet Powering and Transom Depth Effects on Waterjet Priming |
DEC 2007 |
40 pages |
| Authors:
Dominic S. Cusanelli; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD HYDROMECHANICS DIRECTORATE
|
| This report is a partial documentation a series of model-scale experiments conducted 5/07-6/07, on Mixed-Flow Waterjet (MxwJ) Model 5662-1, a waterjet propelled variant of the Joint High Speed Sealift (JHSS) hull platform. This document contains data and evaluations from initial investigations into the following two waterjet topic areas: (1) The effects of model yaw angles on waterjet powering. Model-scale rotor force measurements of thrust and torque at angles of yaw ... |
|
| Math-Based Simulation Tools and Methods |
10 OCT 2007 |
17 pages |
| Authors:
Sudhakar Arepally; ARMY RESEARCH DEVELOPMENT AND ENGINEERING COMMAND WARREN MI
|
| These briefing charts review numerous mathematical methods for simulating crashworthiness and occupant protection in motor vehicles. The following methods are reviewed: matrix operations, ordinary and partial differential system of equations, Lagrangian operations, Fourier transforms, Taylor Series, Finite Difference Methods, implicit and explicit finite element methods, and statistical methods (probabilistic and regression analysis). The slides are labeled as follows: HMMWV 30-mph Rollover Test, Soldier Gear Effects, Occupant Performance in Blast Effects, ... |
|
| Angular Dependence of the Microwave-Generation Threshold in a Nanoscale Spin-Torque Oscillator |
20-Jul-2007 |
5 pages |
| Authors:
G Gerhart; E Bankowski; G A Melkov; V S Tiberkevich; A N Slavin; ARMY TANK-AUTOMOTIVE RESEARCH AND DEVELOPMENT COMMAND WARREN MI
|
| It is shown that in a spin-torque microwave oscillator based on a magnetic nanocontact, the nature of the microwave spin wave mode generated at the threshold critically depends on the angle between the external bias magnetic field and the plane of the free layer. When the external bias field is rotating from normal to in-plane orientation, an abrupt transition from a propagating cylindrical wave with the frequency higher than the ... |
|
| Enhanced Ultrasound Visualization of Brachytherapy Seeds by a Novel Magnetically Induced Motion Imaging Method |
01 APR 2007 |
15 pages |
| Authors:
Stephen McAleavey; ROCHESTER UNIV NY
|
| We report our progress in developing Magnetically Induced Motion Imaging (MIMI) for unambiguous identification and localization brachytherapy seeds in ultrasound images. In this period we have used finite-element models to determine a torque maximizing seed core shape to generate the greatest possible seed vibration for a given core volume. We present two new signal-processing methods. The first is a compounding method for suppression of "comet-tail" artifacts in segmented seed images. ... |
|
| Optimal Spacecraft Attitude Control Using Aerodynamic Torques |
MAR 2007 |
91 pages |
| Authors:
Michael L. Gargasz; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| This thesis introduces a method of three-axis spacecraft attitude control using only aerodynamic torques. Attitude actuation is achieved using four control panels mounted on the rear of a cubical spacecraft bus. The controller consists of an outer loop using linear state feedback to determine desired control torque and an inner loop to choose appropriate control panel angles. The inner loop uses a Jacobian-based approach to invert the nonlinear relationship between ... |
|
| Transportation Vibration Analysis of the XM982 Projectile |
FEB 2007 |
23 pages |
| Authors:
J. Lee; S. Groeschler; ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER PICATINNY ARSENAL NJ
|
| Vibration testing, simulating ground vehicle transportation was performed on the Excalibur and resulted in unexpected responses of the projectile. Modeling and simulation was used to replicate the vibration test and determine the merits of different mounting configurations to secure the round. The mounting configurations were compared based on levels of projectile rotation and torque. |
|
| The Serret-Andoyer Formalism in Rigid-Body Dynamics: 1. Symmetries and Perturbations |
2007 |
38 pages |
| Authors:
P. Gurfil; A. Elipe; W. Tangren; M. Efroimsky; NAVAL OBSERVATORY WASHINGTON DC
|
| This paper reviews the Serret Andoyer (SA) canonical formalism in rigid-body dynamics, and presents some new results. As is well known, the problem of unsupported and unperturbed rigid rotator can be reduced. The availability of this reduction is offered by the underlying symmetry, that stems from conservation of the angular momentum and rotational kinetic energy. When a perturbation is turned on, these quantities are no longer preserved. Nonetheless, the language ... |
|
| Design and Integration of a Three Degrees-of-Freedom Robotic Vehicle with Control Moment Gyro for the Autonomous Multi-Agent Physically Interacting Spacecraft (AMPHIS) Testbed |
SEP 2006 |
93 pages |
| Authors:
Jason S. Hall; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| The use of fractionated spacecraft systems in on-orbit spacecraft assembly has the potential to provide benefits to both the defense and civil space community. To this end, much research must be conducted to develop and prove the requisite technologies to achieve these benefits. This thesis contributes to that effort by presenting the design and system integration, operating procedures and software development for a prototype three Degrees-Of-Freedom (DOF) Spacecraft Simulator. This ... |
|
| Position Analysis of Planar Tensegrity Structures |
AUG 2006 |
108 pages |
| Authors:
Jahan B. Bayat; FLORIDA UNIV GAINESVILLE CENTER FOR INTELLIGENT MACHINES AND ROBOTICS
|
| Tensegrity is an abbreviation of tension and integrity. Tensegrity structures are spatial structures formed by a combination of rigid elements in compression (struts) and connecting elements that are in tension (ties). In three-dimensional tensegrity structures no pair of struts touches, and the end of each strut is connected to non-coplanar ties, which are in tension. In two-dimensional tensegrity structures, struts still do not touch. A tensegrity structure stands by itself ... |
|
| Cost-Benefit Analysis of a Notational Fractionated SATCOM Architecture |
May-2006 |
18 pages |
| Authors:
O Brown; P Bremenko; C Roberts; DEFENSE ADVANCED RESEARCH PROJECTS AGENCY ARLINGTON VA
|
| The basic functions of a typical satellite, distilled to their quintessence, include only the absorption, processing, and subsequent re-radiation of photons. To this end, spacecraft components need only be able to exchange energy--which tends to be dichotomized into power and information--and transmit the occasional force or torque. Perfectly adequate and efficient mechanisms for accomplishing both of these tasks without resorting to a connecting solid structure exist. Perhaps the most philosophically ... |
|
| Combined Singularity Avoidance for Variable Speed Control Moment Gyroscope Clusters |
18 APR 2006 |
16 pages |
| Authors:
David J. Richie; Vaios J. Lappas; Sajjad Asghar; Phil L. Palmer; SURREY UNIV GUILDFORD (UNITED KINGDOM)
|
| Variable Speed Control Moment Gyroscopes (VSCMGs), defined by Schaub in [1], effectively applied to combined energy storage and attitude control in [2,3], and further studied by Yoon and Tsiotras in [4,5], can avoid attitude singularities by varying wheel speed. However, this device's key advantage lies in torque amplification via gimballing (i.e. operating in its CMG mode). The primary limitation of this CMG mode, though, is the existence of gimbal-lock singularity ... |
|
| Enhanced ULtrasound Visualization of Brachytherapy Seeds by a Novel Magnetically Induced Motion Image Method |
APR 2006 |
16 pages |
| Authors:
Stephen McAleavey; ROCHESTER UNIV NY
|
| We report our progress in developing Magnetically Induced Motion Imaging (MIMI) for unambiguous identification and localization brachytherapy seeds in ultrasound images. In this period we have developed finite-element models for calculating the force on a soft ferromagnetic seed core due to geometrical anisotropy and compared two candidate seed geometries to determine the sensitivity of torque to geometry. We have created a finite element model of a prototype coil configuration for ... |
|
| Neural Network Predictions of the 4-Quadrant Wageningen Propeller Series |
APR 2006 |
78 pages |
| Authors:
Robert F. Roddy; David E. Hess; Will Faller; DAVID TAYLOR MODEL BASIN WASHINGTON DC HYDROMECHANICS LAB
|
| The Maneuvering and Control Division of the Naval Surface Warfare Center (NSWC) along with Applied Simulation Technologies have been developing and applying neural networks to problems of naval interest. This report describes the development of feedforward neural network (FFNN) predictions of four-quadrant thrust and torque behavior for the Wageningen B-Screw Series of propellers and for two Wageningen ducted propeller series. The purpose of the work is twofold: to create a ... |
|
| Experimental Analysis of Propeller Interactions With a Flexible Wing Micro-Air-Vehicle |
23 MAR 2006 |
149 pages |
| Authors:
Brian J. Gamble; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
|
| An investigation into the effects of the propeller slipstream on a flexible wing micro-air-vehicle (MAV) was conducted. The Air Force Research Lab, Munitions Directorate designed a man-portable MAV with a 24 in. wingspan and 6 in. root chord to be used for battle damage assessment and reconnaissance. Two wings have been developed for this MAV. One is a rigid carbon-fiber wing and the other consists of flexible parachute material attached ... |
|
| Enhanced Ultrasound Visualization of Brachytherapy Seeds by a Novel Magnetically Induced Motion Imaging Method |
02 NOV 2005 |
7 pages |
| Authors:
Stephen McAleavey; DUKE UNIV DURHAM NC
|
| The authors report on their progress in developing Magnetically Induced Motion Imaging (MIMI) for unambiguous identification and localization of brachytherapy seeds in ultrasound images. Ultrasound guided brachytherapy is a common treatment for prostate cancer. Accurate determination of seed location is critical for the delivery of the correct radiation dose distribution to the prostate. They report initial results from their finite-element model, which provides an estimate of the torque required for ... |
|
| Experimental Investigation of a Lift Augmented Ground Effect Platform |
SEP 2005 |
108 pages |
| Authors:
Roberto T. Igue; AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH SCHOOL OF ENGINEERING
|
| This experimental study investigated the feasibility of applying the concept of a skirtless hovercraft into the production of an operational vehicle. A 0.255 m diameter prototype was designed, built and tested. An air bearing table was used as a testing platform, virtually eliminating the influence of friction and providing one degree of freedom for the experiments. Static tests were performed at various heights and craft configurations, providing a wide range ... |
|
| Magnetic Actuator in Space and Application for High Precision Formation Flying |
13 JUL 2005 |
10 pages |
| Authors:
Thierry Dargent; Massimiliano Maini; ALCATEL SPACE INDUSTRIES CANNES LA BOCCA (FRANCE)
|
| Electromagnetic (EM) actuators in space applications are not a new idea but they are most of the time associated to low Earth orbit missions, where the on-board magnetic moment interacts with the Earth magnetic field. More recently EM actuators have been studied in the context of formation flying as a way to generate inter-spacecraft force and torque in order to control the formation geometry (relative position and attitude of the ... |
|
| Helicopter with Torque-Correcting Thruster Device |
09 MAR 2005 |
30 pages |
| Authors:
James R. Quartarone; DEPARTMENT OF THE NAVY WASHINGTON DC
|
| This patent application discloses a helicopter having a torque-correcting thruster device. The helicopter has an aerodynamic body which has opposite side portions, a top portion and a bottom portion. The aerodynamic body has a cockpit and a pilot seat in the cockpit. The helicopter includes landing gear attached to the bottom portion of the aerodynamic body. The helicopter includes a rotor that is supported by the aerodynamic body and a ... |
|
| In Search of Efficient Walking Robots |
10 JAN 2005 |
7 pages |
| Authors:
Brooke Haueisen; Paul Muench; Greg Hudas; James Overholt; Peter Adamczyk; Greg Hulbert; TACOM RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI
|
| With the recent conflicts in Afghanistan and Iraq, it is increasingly evident that the demands of warfare are changing and the need for innovative mobility systems is growing. In the rough, unstructured terrain that the soldiers encounter, they have reverted to using mules and donkeys to move stealthily and quickly. In light of the growing need for autonomous systems, the Army is looking at the possibility of legged mobility options ... |
|
| Towards a Dynamic Actuator Model for a Hexapod Robot |
2005 |
6 pages |
| Authors:
Dave McMordie; Chris Prahacs; Martin Buehler; MCGILL RESEARCH CENTRE FOR INTELLIGENT MACHINES MONTREAL (QUEBEC)
|
| We describe a model predicting the output torque of the battery-amplifier-actuator-gear combination used on the hexapod robot RHex, based on requested PWM (Pulse-Width-Modulation) duty cycle to the amplifier, battery voltage, and motor speed. The model is broken into independent components, each experimentally validated: power source (battery), motor amplifier, motor, and (planetary) gear. The resulting aggregate model shows 6% Full Scale RMS error in predicting output torque in the first quadrant ... |
|
| Development Of A Control Moment Gyroscope Controlled, Three Axis Satellite Simulator, With Active Balancing For The Bifocal Relay Mirror Initiative |
DEC 2004 |
125 pages |
| Authors:
Wayne J. Kulick; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis develops and implements a Control Moment Gyroscope (CMG) steering law, controller and active balancing system for a three-axis satellite simulator (TASS). The CMGs are configured in a typical pyramid configuration (the fourth CMG position being null). The development was done primarily with simulation and experiments utilizing Real Time Workshop and XPC Target of MATLAB and SIMULINK. The TASS is a double circular platform mounted on a spherical air ... |
|
| Real-Time Optimal Slew Maneuver Design and Control |
DEC 2004 |
179 pages |
| Authors:
Andrew Fleming; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| This thesis considers the problem of time-optimal spacecraft slew maneuvers. Since the work of Bilimoria and Wie it has been known that the time-optimal reorientation of a symmetric rigid body was not the eigenaxis maneuver once thought to be correct. Here, this concept is extended to axisymmetric and asymmetric rigid body reorientations with idealized independent torque generating devices. The premise that the time-optimal maneuver is not, in general, an eigenaxis ... |
|
| Integrated Numerical and Experimental Investigation of Actuator Performance for Guidance of Supersonic Projectiles |
DEC 2004 |
23 pages |
| Authors:
Sidra I. Silton; Kevin C. Massey; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
|
| A recent study showed that the complex 3-D shock/boundary layer interaction of a pin placed next to a fin produces an asymmetric lift force that can be utilized for flight control of a projectile. The current study was completed to validate this new technology. A similar projectile was modeled, using high performance fluid dynamic computations and six degree-of-freedom trajectory simulations, to determine the projectile's flight characteristics prior to being flown ... |
|
| Performance of Propeller 4381 in Crashback |
DEC 2004 |
62 pages |
| Authors:
Christopher J. Chesnakas; Martin J. Donnelly; David J. Fry; Stuart D. Jessup; Joel T. Park; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD HYDROMECHANICS DIRECTORATE
|
| Propeller operation in crashback is technically very challenging, both computationally and experimentally. Propeller 4381 was evaluated experimentally in Carderock's 36-inch (0.91 m) water tunnel. Propeller 4381 was operated in the ahead condition for comparison. Details of the flow field were measured with 3-component laser Doppler velocimetry (LDV) and 2-component particle imaging velocimetry (PIV). Propulsion performance was measured with thrust and torque transducers. Cavitation was documented photographically with a strobe light, ... |
|
| Determination of Laminar Flame Speed of Diesel Fuel for Use in a Turbulent Flame Spread Premixed Combustion Model |
DEC 2004 |
9 pages |
| Authors:
Peter Schihl; John Tasdemir; Walter Bryzik; TACOM RESEARCH DEVELOPMENT AND ENGINEERING CENTER WARREN MI
|
| One of the key challenges facing diesel engine system modelers lies in adequately predicting the fuel burning rate profile given the direct relationship between energy release and key performance parameters such as fuel economy, torque, and exhaust emissions. Current state-of-the-art combustion sub- models employed in such system simulation codes rely heavily on empiricism, and successful application of such sub-models for new engine designs is highly dependent on past experience with ... |
|
| NPSAT1 Magnetic Attitude Control System Algorithm Verification, Validation, and Air-Bearing Tests |
SEP 2004 |
211 pages |
| Authors:
Eric W. Herbert; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
|
| NPSAT1 is a gravity gradient friendly, prolate body designed to fly at 600 40 km inclined to 34.5 degrees. The satellite uses a magnetic 3-axis active attitude control system (ACS) using magnetic torque rods that interact with the Earth's magnetic field. This thesis accomplishes three goals. The first objective was to verify and to validate the magnetic attitude control system program and model developed by Leonard. The verification and validation ... |
|
| A Detailed Study of the Flowfield of a Submarine Propeller During a Crashback Maneuver |
AUG 2004 |
200 pages |
| Authors:
David H. Bridges; MISSISSIPPI STATE UNIV MISSISSIPPI STATE DEPT OF AEROSPACE ENGINEERING
|
| An extensive study of crashback was performed in the U.S. Navy's William B. Morgan Large Cavitation Channel (LCC), located in Memphis, TN. Propeller 4381 was attached to a standard axisymmetric submarine hull model (DTMB Model 5495-3) which was then suspended in the LCC. Forces and moments were measured on both the body and the propeller for steady and unsteady crashback conditions. The unsteady conditions were simulated by allowing the propeller ... |
|
| Magnetic Induction Machines Embedded in Fusion-Bonded Silicon |
JUN 2004 |
5 pages |
| Authors:
David P. Arnold; Florent Cros; Iulica Zana; Mark G. Allen; Sauparna Das; Jeffrey H. Lang; GEORGIA INST OF TECH ATLANTA SCHOOL OF ELECTRICAL AND COMPUTER ENGINEERING
|
| This paper presents the design, fabrication, and characterization of laminated, magnetic induction machines intended for high-speed, high-temperature, high-power-density microengine power generation systems. Innovative fabrication techniques were used to embed electroplated materials (Cu, Ni80Fe20, Co65Fe18Ni17) within etched and fusion-bonded silicon to form the machine structure. The induction machines were characterized in motoring mode using tethered rotors, and exhibited a maximum measured torque of 2.5 N m and a projected torque density ... |
|
| Investigation of Gear and Bearing Fatigue Damage Using Debris Particle Distributions |
MAY 2004 |
16 pages |
| Authors:
Paula J. Dempsey; David G. Lewicki; Harry J. Decker; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH GLENN RESEARCH CENTER
|
| A diagnostic tool was developed for detecting fatigue damage to spur gears, spiral bevel gears, and rolling element bearings. This diagnostic tool was developed and evaluated experimentally by collecting oil debris data from fatigue tests performed in the NASA Glenn Spur Gear Fatigue Rig, Spiral Bevel Gear Test Facility, and the 500 hp Helicopter Transmission Test Stand. During each test, data from an on-line, in-line, inductance type oil debris sensor ... |
|
| Leakage and Power Loss Test Results for Competing Turbine Engine Seals |
MAY 2004 |
16 pages |
| Authors:
Margaret P. Proctor; Irebert R. Delgado; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH GLENN RESEARCH CENTER
|
| Advanced brush and finger seal technologies offer reduced leakage rates over conventional labyrinth seals used in gas turbine engines. To address engine manufacturers' concerns about the heat generation and power loss from these contacting seals, brush, finger, and labyrinth seals were tested in the NASA High Speed, High Temperature Turbine Seal Test Rig. Leakage and power loss test results are compared for these competing seals for operating conditions up to ... |
|
| Fluorpolymer Property Enhancement via Incorporation of Fluorinated Polyhedral Oligomeric Silsesquioxanes (FluoroPOSS) |
12 MAR 2004 |
13 pages |
| Authors:
Joseph M. Mabry; Darrell Marchant; Brent D. Viers; Patrick N. Ruth; Scott Barker; ENGINEERING RESEARCH AND CONSULTING INC(ERC INC) EDWARDS AFB CA
|
| Fluorinated Polyhedral Oligomeric Silsesquioxanes (FluoroPOSS) are the newest class of POSS compounds. These compounds have the highest molecular weights and highest densities of any POSS compounds yet produced. They also have remarkable surface properties, which have been observed in water contact angle measurements. A number of FluoroPOSS compounds have been produced from their respective trifunctional monomers. These FluoroPOSS compounds have been blended into several fluoropolymers, including fluorinated ethylene-propylene (FEP), poly(chlorotrifluoroethylene) ... |
|
| An Electromagnetic Tool for Damping and Fatigue Analysis |
MAR 2004 |
109 pages |
| Authors:
Todd M. Hoover; AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| An automated test system was developed by the USAF Turbine Engine Fatigue Facility (TEFF). This system was initially designed to reduce the time and manpower required to characterize damping treatments. It is based on a digitally controlled environmental chamber with automated data acquisition and processing. Several outputs are available including identification of natural frequencies, modal damping ratios from the acquiries frequency responses, and changes in damping with response amplitude; however, ... |
|
| Exhaust Emissions From a 6.5L Diesel Engine Using Synthetic Fuel and Low-Sulfur Diesel Fuel |
DEC 2003 |
32 pages |
| Authors:
Edwin A. Frame; Matthew G. Blanks; SOUTHWEST RESEARCH INST SAN ANTONIO TXBELVOIR FUELS AND LUBRICANTS RESEARCHFACILITY
|
| Synthetic fuel designated S-5 was evaluated for exhaust emissions and fuel consumption in a 6.5L diesel engine. The S-5 fuel produced substantial reduction in exhaust particulate matter compared to low-sulfur certification diesel fuel over two different transient test cycles. In general the S-5 fuel produced lower exhaust emission levels and slightly reduced brake specific fuel consumption over both test cycles. |
|
| Robust Momentum Manager Controller for Space Station Applications (CD-ROM) |
02 JUL 2003 |
|
| Authors:
Andy C. Lee; RICE UNIV HOUSTON TX
|
 | ELECTRONIC FILE CHARACTERISTICS: 3 files; Adobe Acrobat (.PDF), MS Word (.DOC), and MS PowerPoint (.PPT). PHYSICAL DESCRIPTION: 1 computer laser optical disc (CD-ROM); 4 3/4 in.; 10.8 MB. SYSTEMS DETAIL NOTE: IBM-clone PC-compatible. ABSTRACT: An innovative methodology to design a robust Control Momentum Gyro (CMG) momentum manager for the International Space Station (ISS) is developed. Unlike most other momentum manager designs, which use either a Linear Quadratic Regular (LQR) or ... |
|
| FlexTAC: An Advanced Submarine Control Surface and Actuation System |
JUL 2003 |
39 pages |
| Authors:
Scott Gowing; Bernie Carpenter; Yu T. Lee; Paisan Atsavapranee; David Hess; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD POPULATION AND FLUIDSSYSTEMS DEPT
|
| An electrically-actuated flexible tab was tested on a model of a submarine sternplane comprised of a fixed stabilizer with a hinged flap. The tab was built into the trailing edge of the flap and was tested for its ability to control overall lift and reduce the torque required to rotate the flap itself. Shape memory alloy wires, embedded in a flexible silicone compound along the length of the tab, pulled ... |
|
| High Power Orbit Transfer Vehicle |
JUL 2003 |
216 pages |
| Authors:
Frank S. Gulczinski III; Christopher D. Hall; Lyon B. King; Gordon G. Parker; Martin D. Tervo; AIR FORCE RESEARCH LAB EDWARDS AFB CA SPACE AND MISSILE PROPULSION DIV
|
| The Air Force Research Laboratory Propulsion Directorate's Spacecraft Propulsion Branch has carried out an in-house propulsion trade study and contracted for two other propulsion design studies from Virginia Tech University and Aerophysics, Inc. to examine propulsion requirements for a high-power orbit transfer vehicle using thin-film voltaic solar array technologies under development by the Space Vehicles Directorate (dubbed PowerSail). The in-house study assumed a 100-kilowatt array and performed the most in-depth ... |
|
| Overview of the Electrodynamic Delivery Express (EDDE) |
JUL 2003 |
15 pages |
| Authors:
Jerome Pearson; Joseph Carroll; Eugene Levin; John Oldson; Paul Hausgen; STAR INC MOUNT PLEASANT SC
|
| The ElectroDynamic Delivery Express (EDDE) is an autonomous space vehicle that can deliver multiple small satellites from any low earth orbit (LEO) to any other desired low earth orbit within months, without using fuel. EDDE uses solar power to drive multiampere currents through a multi-kilometer aluminum tape. The tape sees a force normal to both itself and the local magnetic field. The tape is electrically connected to the ambient ionosphere ... |
|
| Micro Piezoelectric Ultrasonic Motors |
17 JUN 2003 |
11 pages |
| Authors:
Kenji Uchino; S. Cagatay; B. Koc; S. Dong; P. Bouchilloux; PENNSYLVANIA STATE UNIV UNIVERSITY PARK
|
| This paper reviews recent developments of micro ultrasonic rotary motors using piezoelectric resonant vibrations. Following the historical background, four ultrasonic motors recently developed at Penn State University are introduced: windmill, PZT tube, metal tube, and shear-type motors. Driving principles and motor characteristics are described in comparison with the conventional ultrasonic motors. Motors with 1.5mm in diameter and O.8mNm in torque have been actually developed. |
|
| Ultrasonic Motors |
JUN 2003 |
15 pages |
| Authors:
Serra Cagatay; Kenji Uchino; Burbanettin Koc; PENNSYLVANIA STATE UNIV UNIVERSITY PARK
|
| Ultrasonic motors, which have superior characteristics like high torque at low speed, absence of magnetic interference, and compactness in size, are good candidates for medical applications, automation, robotics, aerospace engineering and various other fields. Many different types of ultrasonic motors have been proposed up to date. The stator of an ultrasonic motor that is excited by piezoelectric elements in ultrasonic frequency range develops different kinds of vibrations depending on its ... |
|
| Design And Simulation of a Three-Axis Stabilized Satellite and Kalman Filter Rate Estimator |
JUN 2003 |
114 pages |
| Authors:
John Vitalich; NAVAL POSTGRADUATE SCHOOL MONTEREY CA DEPT OF ELECTRICAL AND COMPUTER ENGINEERING
|
| Design requirements for a small satellite (NPSAT-l) Attitude Determination and Control Subsystem (ADCS) is a three-axis stabilized spacecraft which requires a control attitude of +/- 1,0 degrees and knowledge attitude of +/- 0,1 degree. Several design aspects are considered in development of attitude control systems for a small satellite, such as: spacecraft dynamics, space environment, disturbance torques, orbit type, and spacecraft complexity. The ideal spacecrafts attitude sensor is a rate ... |
|
| NPSAT1 Attitude Control Subsystem Hardware-in-the-Loop Simulation |
05 MAY 2003 |
186 pages |
| Authors:
Alexander Schmidt; NAVAL POSTGRADUATE SCHOOL MONTEREY CA SPACE SYSTEMS ACADEMIC GROUP
|
| NPSAT1 is a three-axis stabilized spacecraft. Its Attitude Control Subsystem (ACS) uses a magnetic control approach that will be used for the first time. The Magnetic control approach is verified with an ACS SIMULINK model of NPSAT1. The correct SIMULINK implementation of the magnetic control algorithm will be verified with an ACS air bearing SIMULINK model and a hardware-embedded ACS control algorithm SIMULINK model that controls the test platform on ... |
|
| Effects on Diagnostic Parameters After Removing Additional Synchronous Gear Meshes |
APR 2003 |
14 pages |
| Authors:
Harry J. Decker; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH GLENN RESEARCH CENTER
|
| Gear cracks are typically difficult to diagnose with sufficient time before catastrophic damage occurs. Significant damage must be present before algorithms appear to be able to detect the damage. Frequently there are multiple gear meshes on a single shaft. Since they are all synchronous with the shaft frequency, the commonly used synchronous averaging technique is ineffective in removing other gear mesh effects. Carefully applying a filter to these extraneous gear ... |
|
| Design and Analysis of a Flipping Controller for RHex |
2003 |
19 pages |
| Authors:
Uluc Saranli; Daniel E. Koditschek; MICHIGAN UNIV ANN ARBOR DEPT OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE
|
| We report on the design and analysis of a controller that can achieve dynamical self-righting of our hexapedal robot, RHex. We present an empirically tuned controller that works reasonably well on indoor surfaces, using a hybrid energy pumping strategy to overcome torque limitations of its actuators. Subsequent modeling and analysis yields a new controller with a much wider domain of success as well as a preliminary understanding of the hybrid ... |
|
| Flow Predictions for Multi-Element Control Surfaces |
DEC 2002 |
28 pages |
| Authors:
Yu-Tai Lee; Michael P. Ebert; Ashvin Hosangadi; NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
|
| The TAC (Tab-Assisted Control) and FlexTAC (Flexible Tab-Assisted Control) airfoils based on NACA 0018 sections are conceptual multi-element airfoil designs for future marine vehicle control surfaces. In addition to a relative motion between the stabilizer and the flap, either a rigid (for TAC) or a flexible (for FlexTAC) tab is used to augment the functionality of the control surfaces. The TAC airfoil has a front and a rear gap while ... |
|
| The Lageos Satellite: A Comprehensive Spin Model and Analysis |
DEC 2002 |
267 pages |
| Authors:
Scott E. Williams; AIR FORCE ACADEMY COLORADO SPRINGS CO DEPT OF MATHEMATICS
|
| A thorough investigation into the theoretical modeling of the Laser- Ranged Geodynamics Satellite (Lageos I) spin state evolution is presented. Starting from an existing dynamical model, we analyze in detail each of the model's assumptions and explore possible enhancements. Additional concerns not considered by the original model are also scrutinized in a bottom-up approach. In particular, we re-evaluate the orbit propagation module, survey and investigate all possible space-environment effects, assess ... |
|
| Design and Testing of Three-Axis Satellite Attitude Determination and Stabilization Systems That Are Based on Magnetic Sensing and Actuation |
27 NOV 2002 |
55 pages |
| Authors:
Mark L. Psiaki; Moshe Guelman; CORNELL UNIV ITHACA NY
|
| Three-axis satellite attitude determination and active stabilization systems have been designed and tested using both flight experiments and simulation studies. These are being developed for use on low-Earth-orbiting name- satellites. Such satellites can be used as elements of constellations that implement synthetic aperture radar or that serve as nodes in a communications network. The research has addressed the problems of under-sensing and under- actuation that are present in magnetic-based systems. ... |
|
| The Effect of Walking Speed and Adding a Backpack on Trunk Dynamics During Treadmill Walking |
OCT 2002 |
40 pages |
| Authors:
Michael LaFiandra; Robert Wagenaar; Kenneth Holt; John P. Obusek; ARMY RESEARCH INST OF ENVIRONMENTAL MEDICINE NATICK MA MILITARY PERFORMANCEDIV
|
| To determine the effects of load carriage and walking speed on stride parameters and the coordination of trunk movements, twelve subjects walked on a level treadmill at a range of walking speeds (0.6 m/s - 1.6 m/s) with and without a backpack containing 40% of their body mass. It was hypothesized that compared to unloaded walking load carriage decreases transverse pelvic and thoracic rotation, the mean relative phase between pelvic ... |
|
Reports by Keyword(s)
TORQUE
