Single Network Adaptive Critics Networks-Development, Analysis, And Applications,
2013
Missouri University of Science and Technology
Single Network Adaptive Critics Networks-Development, Analysis, And Applications, Jie Ding, Ali Heydari, S. N. Balakrishnan
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Solving infinite time optimal control problems in an approximate dynamic programing framework with two-network structure has become popular in recent years. In this chapter, an alternative to the two-network structure is provided. We develop single network adaptive critics (SNAC) which eliminate the need to have a separate action network to output control. Two versions of SNAC are presented. The first version, called SNAC outputs the costates and the second version called J-SNAC outputs the cost function values. Special structure called Finite-SNAC to efficiently solve finite time problems is also presented. Illustrative infinite time and finite time problems are considered; numerical …
Smaller Spacecraft For Flying Large Clusters Of Biological Space Experiments,
2013
Morehead State University
Smaller Spacecraft For Flying Large Clusters Of Biological Space Experiments, Robert J. Twiggs
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint presentation created by Professor Bob Twiggs titled "Smaller spacecraft for flying large clusters of biological space experiments" from February 5, 2013.
Would I Survive In Space?,
2013
Morehead State University
Would I Survive In Space?, Robert J. Twiggs
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint presentation created by Professor Bob Twiggs titled "Would I survive in Space?" from February 4, 2013.
Smore Revision: Ignition And User Interface,
2013
California Polytechnic State University, San Luis Obispo
Smore Revision: Ignition And User Interface, Arash Mehrparvar
Aerospace Engineering
The Static Methanol Oxygen Rocket Engine (SMORE) has undergone several revisions since its inception. This latest revision aimed to increase startup reliability and user safety in the operation of the rocket. The implementation of maintenance procedures, safeguards in the ignition system, as well as construction of a new control box and redesign of the igniter itself have accomplished these goals while keeping costs down and without modifying the current rocket setup. Startup reliability has increased drastically, so long as all other rocket setup procedures are followed properly. 250 subsequent firings of the rocket have proven an igniter reliability of more …
Validation Of Proposed Metrics For Two-Body Abrasion Scratch Test Analysis Standards: In Principle, Any Scratch Can Be Analyzed By This Method,
2013
NASA Glenn Research Center
Validation Of Proposed Metrics For Two-Body Abrasion Scratch Test Analysis Standards: In Principle, Any Scratch Can Be Analyzed By This Method, Kenneth W. Street, Ryan L. Kobrick, David M. Klaus
Publications
Abrasion of mechanical components and fabrics by soil on Earth is typically minimized by the effects of atmosphere and water. Potentially abrasive particles lose sharp and pointed geometrical features through erosion. In environments where such erosion does not exist, such as the vacuum of the Moon, particles retain sharp geometries associated with fracturing of their parent particles by micrometeorite impacts. The relationship between hardness of the abrasive and that of the material being abraded is well understood, such that the abrasive ability of a material can be estimated as a function of the ratio of the hardness of the two …
Numerical Modeling Of Anti-Icing Using An Array Of Heated Synthetic Jets,
2013
Embry-Riddle Aeronautical University
Numerical Modeling Of Anti-Icing Using An Array Of Heated Synthetic Jets, Nikisha Maria Nagappan
Doctoral Dissertations and Master's Theses
A novel approach to icing control using an array of thermally activated synthetic jet actuators (SJAs) embedded in a wedge surface subject to a super-cooled flow is investigated numerically. The effects of SJA actuation with and without jet heating on ice accretion are studied using the FENSAP-ICE software. It is shown that the heated actuating SJAs can lead to a significant reduction in the amount of ice accreted on the surface. Additional parametric studies on several icing and SJA parameters are analyzed for their influence on the amount of ice accretion.
Guided Wave-Based J-Integral Estimation For Dynamic Stress Intensity Factors Using 3d Scanning Laser Doppler Vibrometry,
2013
US Army Research Laboratory
Guided Wave-Based J-Integral Estimation For Dynamic Stress Intensity Factors Using 3d Scanning Laser Doppler Vibrometry, J. Ayers, Christopher Todd Owen, Eric D. Swenson, Anindya Ghoshal, V. Weiss
Faculty Publications
The application of guided waves to interrogate remote areas of structural components has been researched extensively in characterizing damage. However, there exists a sparsity of work in using piezoelectric transducer-generated guided waves as a method of assessing stress intensity factors (SIF). This quantitative information enables accurate estimation of the remaining life of metallic structures exhibiting cracks, such as military and commercial transport vehicles. The proposed full wavefield approach, based on 3D laser vibrometry and piezoelectric transducer-generated guided waves, provides a practical means for estimation of dynamic stress intensity factors (DSIF) through local strain energy mapping via the J-integral. Strain energies …
Electric Motor Modeling For Conceptual Aircraft Design,
2013
California Polytechnic State University - San Luis Obispo
Electric Motor Modeling For Conceptual Aircraft Design, Robert A. Mcdonald
Aerospace Engineering
Electric motors have achieved very high efficiency and reliability; and in some cases, very high specific power. As the energy storage capabilities of batteries and fuel cells advance, these technologies are increasingly being considered for aircraft primary propulsion. In order to design electric aircraft, aircraft designers must be able to understand and model the performance characteristics of electric motors. Most electric machine modeling techniques either ignore potentially important phenomena or require an extreme level of detail undesirable for conceptual aircraft design. In this paper, a compromise approach is proposed which can capture the salient details of motor performance without requiring …
Enabling Rapid Conceptual Design Using Geometry-Based Multi-Fidelity Models In Vsp,
2013
California Polytechnic State University - San Luis Obispo
Enabling Rapid Conceptual Design Using Geometry-Based Multi-Fidelity Models In Vsp, Joel B. Belben, Robert A. Mcdonald
Aerospace Engineering
Four types of reduced fidelity or degenerate geometric representations have been defined and implemented in VSP for the purpose bridging the gap between conceptual design and analysis. They are Degenerate Surface, Degenerate Plate, Degenerate Stick, and Degenerate Point, corresponding to three-, two-, one-, and zero-dimensional representations of underlying geometry, respectively. The information contained in these representations was targeted specifically at lifting line theory, vortex lattice, equivalent beam, and equivalent plate methods, but could be used for other analysis techniques. The ability to output this information in both csv and Matlab file formats has been implemented in VSP. Ongoing work seeks …
Flow Uniformity Calibration Of Amelia's Circulation Control Wings,
2013
California Polytechnic State University - San Luis Obispo
Flow Uniformity Calibration Of Amelia's Circulation Control Wings, Eric N. Paciano, Johnathan A. Lichtwardt, David D. Marshall, Kristina K. Jameson, Robert K. Fong
Aerospace Engineering
This paper details the extensive effort required to achieve uniform now from the AMELIA wind tunnel model's circulation control wings. Performed in September of 2011 in the Fluid Mechanics Lab at NASA Ames Research Center, the calibration required a 500hp instrument-quality air compressor capable of delivering 250 CFM at pressures greater than 70 psL It was found that the geometery within AMELIA's circulation control supply plenums produced highly vortlcal flow, resulting in poor circulation control performance as measured by traversing external and stationary internal total pressure probes, as well as surface oil now. Adjustments were made within AMELIA to the …
Stol Performance Of Cal Poly's Amelia,
2013
California Polytechnic State University - San Luis Obispo
Stol Performance Of Cal Poly's Amelia, Johnathan A. Lichtwardt, Eric N. Paciano, David D. Marshall, Kristina K. Jameson
Aerospace Engineering
Results from Cal Poly's recent wind tunnel test in the 40-by 80-foot test section at the National Full-Scale Aerodynamics Complex (NFAC) at NASA Ames Research Center are presented. AMELIA, the Advanced Model for Extreme Lift and Improved Aeroacoustics, is the first full-span cruise efficient short take-off and landing (CESTOL) model incorporating leading-and trailing-edge blowing wing circulation control and over-the-wing mounted turbine propulsion simulators (TPS) to date. Testing of the 10 foot span model proved successful and was the result of a 5-year NASA Fundamental Aeronautics Program Research Announcement. All of the results associated with Cal Poly's effort will be available …
Cal Poly's Amelia 10 Foot Span Hybrid Wing-Body Low Noise Cestol Aircraft Wing Tunnel Test And Experimental Results Overview,
2013
California Polytechnic State University - San Luis Obispo
Cal Poly's Amelia 10 Foot Span Hybrid Wing-Body Low Noise Cestol Aircraft Wing Tunnel Test And Experimental Results Overview, Kristina K. Jameson, David D. Marshall, Robert Ehrmann, Jonathon A. Lichtwardt, Eric N. Paciano, Robert J. Englar, William C. Hornes
Aerospace Engineering
A collaboration between California Polytechnic Corporation with Georgia Tech Research Institute (GTRI) and DHC Engineering worked on a NASA NRA to develop predictive capabilities for the design and performance of Cruise Efficient, Short Take-Off and Landing (CESTOL) subsonic aircraft. The work presented in this paper gives details of a large scale wind tunnel effort to validate predictive capabilities for this NRA for aerodynamic and acoustic performance during takeoff and landing. The model, Advanced Model for Extreme Lift and Improved Aeroacoustics {AMELIA), was designed as a 100 passenger, N+2 generation, regional, cruise efficient short takeoff and land (CESTOL) airliner with hybrid …
Solar Energy Collection Analysis Tool For Conceptual Aircraft Design,
2013
California Polytechnic State University - San Luis Obispo
Solar Energy Collection Analysis Tool For Conceptual Aircraft Design, Grant M. Glazebrook, Robert A. Mcdonald
Aerospace Engineering
As battery energy storage and solar cell technology improve, solar aircraft are increasingly being considered for high altitude long endurance missions. Although solar vehicles may theoretically remain on station indefinitely using the sun as a power source, their design and feasibility is sensitive to mission planning details as specific as the time history of the vehicle’s deck orientation relative to the sun; the energy available for capture by the on-board solar array is governed by the solar incidence angle, and at certain orientations, the vehicle may cast shadows on itself and further reduce its energy capture capabilities. To quantify these …
Spacecraft Payloads,
2013
Morehead State University
Spacecraft Payloads, Robert J. Twiggs
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint Presentation created by Professor Bob Twiggs on "Spacecraft Payloads" on January 5, 2013.
Systems Engineering,
2013
Morehead State University
Systems Engineering, Robert J. Twiggs
Robert "Bob" Twiggs STEM Education Collection
A PowerPoint Presentation created by Professor Bob Twiggs on "System Engineering" on January 5, 2013.
Akin's Laws Of Spacecraft Design,
2013
Morehead State University
Akin's Laws Of Spacecraft Design, Robert J. Twiggs
Robert "Bob" Twiggs STEM Education Collection
A document use in class by Professor Bob Twiggs titled "Akin's Law of Spacecraft Design" from January 5, 2013.
Comparison Of Models For Mixture Transport Properties For Numerical Simulations Of Ablative Heat-Shields,
2013
University of Michigan
Comparison Of Models For Mixture Transport Properties For Numerical Simulations Of Ablative Heat-Shields, Hicham Alkandry, Iain D. Boyd, Alexandre Martin
Mechanical Engineering Faculty Publications
The goal of this study is to evaluate the effects of different models for calculating the mixture transport properties on flowfield predictions of ablative heat-shields. The Stardust sample return capsule at four different trajectory conditions is used as a test case for this study. In the first part of the study, the results predicted using Wilke's mixing rule with species viscosities calculated using Blottner's curve fits and species thermal conductivities determined using Eucken's relation are compared to the results obtained using Gupta's mixing rule with collision cross-section (CCS) data. The Wilke/Blottner/Eucken model overpredicts the heat transfer to the surface relative …
Investigation Of Turbulent Structure Modification By Momentum Injection Into Turbulent Flow Over A Rough Surface,
2013
University of Kentucky
Investigation Of Turbulent Structure Modification By Momentum Injection Into Turbulent Flow Over A Rough Surface, Mark A. Miller, Huaibao Zhang, Alexandre Martin, Sean C. C. Bailey
Mechanical Engineering Faculty Publications
Utilizing a turbulent channel flow facility, experiments were performed to determine the modifications made to the temporal and spatial structure of turbulence over a sinusoidally rough surface due to momentum injection through the surface. As expected, when compared to the smooth-walled conditions, it was found that the surface roughness increased wall shear stress, decreased the turbulence energy content near the wall, and shifted that energy content to wavelengths on the order of the roughness elements. The addition of momentum injection was found to produce further modifications analogous to increasing the roughness height by increasing the wall shear stress and further …
Modeling Of Chemical Nonequilibrium Effects In A Charring Ablator,
2013
University of Kentucky
Modeling Of Chemical Nonequilibrium Effects In A Charring Ablator, Alexandre Martin
Mechanical Engineering Faculty Publications
Charring ablators remain the premium choice for space exploration missions that involve atmospheric re-entry. These type of ablative material are composed of a carbon matrix, usually made of fibers, which is then impregnated with a resin. During re-entry, the high heat flux produced by convective heating causes the material to chemically react. First, the resin pyrolyzes, and is vaporized into a gas that travels through the material, and is eventually ejected at the surface. Since the composition of the gas at the surface greatly affects the heat flux, and therefore the surface temperature, it is thus important to be able …
Robust Parafoil Terminal Guidance Using Massively Parallel Processing,
2013
Georgia Institute of Technology - Main Campus
Robust Parafoil Terminal Guidance Using Massively Parallel Processing, Jonathan Rogers, Nathan Slegers
Faculty Publications - Biomedical, Mechanical, and Civil Engineering
Terminal guidance of autonomous parafoils is a difficult problem in which wind uncertainty and system underactuation are major challenges. Existing strategies almost exclusively use impact error as the criterion for optimality. Practical airdrop systems, however, must also include other criteria that maybe even more important than impact error for some missions, such as ground speed at impact or constraints imposed by drop zones with restrictions on flight patterns. Furthermore, existing guidance schemes determine terminal trajectories using deterministic wind information and may result in a solution that works in ideal wind but may be sensitive to variations. The work described here …
