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  • ASTROPHYSICS
  • Aircraft Stability and Control
  • Cell & Developmental Biology
  • Inorganic Chemistry
  • 2010-2014  (17)
  • 1980-1984
  • 1955-1959
  • 1905-1909
  • 2013  (17)
  • 1
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    AMELIA CESTOL Test: Acoustic Characteristics of Circulation Control Wing with Leading- and Trailing-Edge Slot Blowing (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-19
    Description: The AMELIA Cruise-Efficient Short Take-off and Landing (CESTOL) configuration concept was developed to meet future requirements of reduced field length, noise, and fuel burn by researchers at Cal Poly, San Luis Obispo and Georgia Tech Research Institute under sponsorship by the NASA Fundamental Aeronautics Program (FAP), Subsonic Fixed Wing Project. The novel configuration includes leading- and trailing-edge circulation control wing (CCW), over-wing podded turbine propulsion simulation (TPS). Extensive aerodynamic measurements of forces, surfaces pressures, and wing surface skin friction measurements were recently measured over a wide range of test conditions in the Arnold Engineering Development Center(AEDC) National Full-Scale Aerodynamics Complex (NFAC) 40- by 80-Ft Wind Tunnel. Acoustic measurements of the model were also acquired for each configuration with 7 fixed microphones on a line under the left wing, and with a 48-element, 40-inch diameter phased microphone array under the right wing. This presentation will discuss acoustic characteristics of the CCW system for a variety of tunnel speeds (0 to 120 kts), model configurations (leading edge(LE) and/or trailing-edge(TE) slot blowing, and orientations (incidence and yaw) based on acoustic measurements acquired concurrently with the aerodynamic measurements. The flow coefficient, Cmu= mVSLOT/qSW varied from 0 to 0.88 at 40 kts, and from 0 to 0.15 at 120 kts. Here m is the slot mass flow rate, VSLOT is the slot exit velocity, q is dynamic pressure, and SW is wing surface area. Directivities at selected 1/3 octave bands will be compared with comparable measurements of a 2-D wing at GTRI, as will as microphone array near-field measurements of the right wing at maximum flow rate. The presentation will include discussion of acoustic sensor calibrations as well as characterization of the wind tunnel background noise environment.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN5354 , 51st AIAA Aerospace Sciences Meeting; Jan 07, 2013 - Jan 10, 2013; Grapevine, TX; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 2
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    Motion-Based Piloted Simulation Evaluation of a Control Allocation Technique to Recover from Pilot Induced Oscillations (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: This paper describes the maturation of a control allocation technique designed to assist pilots in the recovery from pilot induced oscillations (PIOs). The Control Allocation technique to recover from Pilot Induced Oscillations (CAPIO) is designed to enable next generation high efficiency aircraft designs. Energy efficient next generation aircraft require feedback control strategies that will enable lowering the actuator rate limit requirements for optimal airframe design. One of the common issues flying with actuator rate limits is PIOs caused by the phase lag between the pilot inputs and control surface response. CAPIO utilizes real-time optimization for control allocation to eliminate phase lag in the system caused by control surface rate limiting. System impacts of the control allocator were assessed through a piloted simulation evaluation of a non-linear aircraft simulation in the NASA Ames Vertical Motion Simulator. Results indicate that CAPIO helps reduce oscillatory behavior, including the severity and duration of PIOs, introduced by control surface rate limiting.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN10070 , AIAA Guidance, Navigation, and Control Conference; Aug 19, 2013 - Aug 22, 2013; Boston, MA; United States
    Format: application/pdf
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  • 3
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    Virtual Deformation Control of the X-56A Model with Simulated Fiber Optic Sensors (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A robust control law design methodology is presented to stabilize the X-56A model and command its wing shape. The X-56A was purposely designed to experience flutter modes in its flight envelope. The methodology introduces three phases: the controller design phase, the modal filter design phase, and the reference signal design phase. A mu-optimal controller is designed and made robust to speed and parameter variations. A conversion technique is presented for generating sensor strain modes from sensor deformation mode shapes. The sensor modes are utilized for modal filtering and simulating fiber optic sensors for feedback to the controller. To generate appropriate virtual deformation reference signals, rigid-body corrections are introduced to the deformation mode shapes. After successful completion of the phases, virtual deformation control is demonstrated. The wing is deformed and it is shown that angle-of-attack changes occur which could potentially be used to an advantage. The X-56A program must demonstrate active flutter suppression. It is shown that the virtual deformation controller can achieve active flutter suppression on the X-56A simulation model.
    Keywords: Aircraft Stability and Control
    Type: DFRC-E-DAA-TN10283 , AIAA Atmospheric Flight Mechanics Conference; Aug 19, 2013 - Aug 22, 2013; Boston, MA; United States
    Format: application/pdf
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  • 4
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    Descent and Landing Triggers for the Orion Multi-Purpose Crew Vehicle Exploration Flight Test-1 (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The Orion Multi-Purpose Crew Vehicle (MPCV) will perform a flight test known as Exploration Flight Test-1 (EFT-1) currently scheduled for 2014. One of the primary functions of this test is to exercise all of the important Guidance, Navigation, Control (GN&C), and Propulsion systems, along with the flight software for future flights. The Descent and Landing segment of the flight is governed by the requirements levied on the GN&C system by the Landing and Recovery System (LRS). The LRS is a complex system of parachutes and flight control modes that ensure that the Orion MPCV safely lands at its designated target in the Pacific Ocean. The Descent and Landing segment begins with the jettisoning of the Forward Bay Cover and concludes with sensing touchdown. This paper discusses the requirements, design, testing, analysis and performance of the current EFT-1 Descent and Landing Triggers flight software.
    Keywords: Aircraft Stability and Control
    Type: JSC-CN-27920 , 36th Annual AAS Guidance and Control Conference; Feb 01, 2013 - Feb 06, 2013; Breckenridge, CO; United States
    Format: application/pdf
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  • 5
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    Transfer Function Identification Using Orthogonal Fourier Transform Modeling Functions (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: A method for transfer function identification, including both model structure determination and parameter estimation, was developed and demonstrated. The approach uses orthogonal modeling functions generated from frequency domain data obtained by Fourier transformation of time series data. The method was applied to simulation data to identify continuous-time transfer function models and unsteady aerodynamic models. Model fit error, estimated model parameters, and the associated uncertainties were used to show the effectiveness of the method for identifying accurate transfer function models from noisy data.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-15987 , Atmospheric Flight Mechanics Conference; Aug 19, 2013 - Aug 22, 2013; Boston, MA; United States
    Format: application/pdf
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  • 6
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    Global Aerodynamic Modeling for Stall/Upset Recovery Training Using Efficient Piloted Flight Test Techniques (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Flight test and modeling techniques were developed for efficiently identifying global aerodynamic models that can be used to accurately simulate stall, upset, and recovery on large transport airplanes. The techniques were developed and validated in a high-fidelity fixed-base flight simulator using a wind-tunnel aerodynamic database, realistic sensor characteristics, and a realistic flight deck representative of a large transport aircraft. Results demonstrated that aerodynamic models for stall, upset, and recovery can be identified rapidly and accurately using relatively simple piloted flight test maneuvers. Stall maneuver predictions and comparisons of identified aerodynamic models with data from the underlying simulation aerodynamic database were used to validate the techniques.
    Keywords: Aircraft Stability and Control
    Type: NF1676L-15959 , Atmospheric Flight Mechanics Conference; Aug 19, 2013 - Aug 22, 2013; Boston, MA; United States
    Format: application/pdf
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  • 7
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    Performance Enhancement of a Vertical Tail Model with Sweeping Jet Actuators (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Active Flow Control (AFC) experiments performed at the Caltech Lucas Adaptive Wall Wind Tunnel on a 12%-thick, generic vertical tail model indicated that sweeping jets emanating from the trailing edge (TE) of the vertical stabilizer significantly increased the side force coefficient for a wide range of rudder deflection angles and yaw angles at free-stream velocities approaching takeoff rotation speed. The results indicated that 2% blowing momentum coefficient (C(sub mu) increased the side force in excess of 50% at the maximum conventional rudder deflection angle in the absence of yaw. Even C(sub mu) = 0.5% increased the side force in excess of 20% under these conditions. This effort was sponsored by the NASA Environmentally Responsible Aviation (ERA) project and the successful demonstration of this flow-control application could have far reaching implications. It could lead to effective applications of AFC technologies on key aircraft control surfaces and lift enhancing devices (flaps) that would aid in reduction of fuel consumption through a decrease in size and weight of wings and control surfaces or a reduction of the noise footprint due to steeper climb and descent.
    Keywords: Aircraft Stability and Control
    Type: AIAA Paper 2013-0411 , NF1676L-15910 , 51st AIAA Aerospace Sciences Meeting; Jan 07, 2013 - Jan 10, 2013; Grapevine, TX; United States
    Format: application/pdf
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  • 8
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    Beyond Rigid Body: Integrated Structural Control of Extremely Lightweight Flexible Aircraft (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: Integrated structural control of extremely lightweight vehicles will open a new paradigm and allow for performance increases. The X-56A Multi-Utility Technology Testbed (MUTT) vehicle will be used to evaluate and advance the state-of-the-art in modeling and control of this new class of aerospace vehicle.
    Keywords: Aircraft Stability and Control
    Type: DFRC-E-DAA-TN7649
    Format: application/pdf
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  • 9
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    Generalized Predictive Control of Dynamic Systems with Rigid-Body Modes (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: Numerical simulations to assess the effectiveness of Generalized Predictive Control (GPC) for active control of dynamic systems having rigid-body modes are presented. GPC is a linear, time-invariant, multi-input/multi-output predictive control method that uses an ARX model to characterize the system and to design the controller. Although the method can accommodate both embedded (implicit) and explicit feedforward paths for incorporation of disturbance effects, only the case of embedded feedforward in which the disturbances are assumed to be unknown is considered here. Results from numerical simulations using mathematical models of both a free-free three-degree-of-freedom mass-spring-dashpot system and the XV-15 tiltrotor research aircraft are presented. In regulation mode operation, which calls for zero system response in the presence of disturbances, the simulations showed reductions of nearly 100%. In tracking mode operations, where the system is commanded to follow a specified path, the GPC controllers produced the desired responses, even in the presence of disturbances.
    Keywords: Aircraft Stability and Control
    Type: NASA/TM-2013-217976 , NF1676L-15781 , L-20211
    Format: application/pdf
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  • 10
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    Real-Time Optimization for use in a Control Allocation System to Recover from Pilot Induced Oscillations (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Integration of the Control Allocation technique to recover from Pilot Induced Oscillations (CAPIO) System into the control system of a Short Takeoff and Landing Mobility Concept Vehicle simulation presents a challenge because the CAPIO formulation requires that constrained optimization problems be solved at the controller operating frequency. We present a solution that utilizes a modified version of the well-known L-BFGS-B solver. Despite the iterative nature of the solver, the method is seen to converge in real time with sufficient reliability to support three weeks of piloted runs at the NASA Ames Vertical Motion Simulator (VMS) facility. The results of the optimization are seen to be excellent in the vast majority of real-time frames. Deficiencies in the quality of the results in some frames are shown to be improvable with simple termination criteria adjustments, though more real-time optimization iterations would be required.
    Keywords: Aircraft Stability and Control
    Type: ARC-E-DAA-TN10068 , AIAA Guidance, Navigation, and Control Conference; Aug 19, 2013 - Aug 22, 2013; Boston, MA; United States
    Format: application/pdf
    Location Call Number Expected Availability
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