Recent Submissions

  • Adaptive control of coupled dynamical systems: a mixed state and output feedback framework 

    Yucelen, Tansel; Gruenwald, Benjamin C.; Merve Dogan, Kadriye; Chakravarthy, Animesh; Menon, Alok N. (Taylor and Francis Ltd, 2019-10-15)
    This paper studies a class of coupled dynamical systems consisting of an actuated dynamical system interconnected with an unactuated dynamical system. The actuated dynamical system is considered to have a measurable state ...
  • Objective function weight selection for sequential low-thrust orbit-raising optimization problem 

    Dutta, Atri; Arora, Lakshay (Univelt Inc., 2019-01)
    In this paper, we consider the low-thrust orbit-raising problem formulated as a sequence of optimal control sub-problems. This formulation is helpful in rapid and robust generation of geocentric electric orbit-raising ...
  • Flight loads spectra of a fleet of heavy air tankers 

    Rokhsaz, Kamran; Kliment, Linda K.; Terning, Brett R.; Nelson, John A. (American Institute of Aeronautics and Astronautics Inc., 2019-06-10)
    In-flight recorded data from eight BAe-146s and eight RJ-85s flown in support of the United States Forest Service aerial firefighting operations have been analyzed. Flights have been divided into firefighting, ferry, and ...
  • Spacecraft maneuver detection using optimal control theory and equations of relative motion 

    Dutta, Atri; Raquepas, Joseph B. (Univelt Inc., 2018)
    In this paper, we investigate the spacecraft maneuver detection problem by considering an optimal control formulation, in which we minimize the control effort subject to the Hill-Clohessy-Wiltshire equations of relative ...
  • Relative equations of motion using a new set of orbital elements 

    Chadalavada, Pardhasai; Dutta, Atri (Univelt Inc., 2018)
    In this paper, we consider the relative equations of spacecraft motion in terms of a new set of orbital elements that includes the components of the angular momentum in the inertial reference frame, the components of the ...
  • Control of a flexible wing with flaps using a set theoretic active-passive framework 

    Menon, Alok N.; Chakravarthy, Animesh; Gruenwald, Benjamin C.; Yucelen, Tansel (American Institute of Aeronautics and Astronautics Inc., 2019-01-06)
    This paper develops a distributed parameter model for a multiple component structure morphing, flexible wing aircraft with a n trailing edge rigid flaps. Using a set-theoretic adaptive control approach that utilizes ...
  • Simulated flight testing of an adaptive loss-of-control avoidance pilot advisory display 

    Rafi, Melvin; Rajaram, Kiran; Moustafa, Mohamed A.; Bin Salmaan Hussain, Danial Imran; Morales, Kevin; Steck, James E.; He, Jibo; Chakravarthy, Animesh (American Institute of Aeronautics and Astronautics Inc., 2019-01-06)
    Loss-of-Control has been consistently deemed the primary contributor to air accidents globally. Systems capable of alerting pilots when impending control loss is predicted to occur have the potential to promote safer flight. ...
  • Retrofit winglets for wind turbines 

    Matheswaran, Vijay; Miller, Leonard Scott; Moriarty, Patrick J. (American Institute of Aeronautics and Astronautics Inc., 2019-01-06)
    The benefits of using winglets on wind turbines has been well documented. However, adding winglets to wind turbine blades leads to significant increases in blade root bending moments, requiring expensive structural ...
  • Machine learning applied to programming quantum computers 

    Steck, James E.; Behrman, Elizabeth C.; Thompson, Nathan (American Institute of Aeronautics and Astronautics, 2019-01-06)
    We apply machine learning to “program” quantum computers, both in simulation and in experimental hardware. A major difficulty in quantum computing is developing effective algorithms that can be programmed on a quantum ...
  • Real-time adaptive prediction of loss-of-control margins on a fourth order aircraft 

    Rafi, Melvin; Steck, James E.; Chakravarthy, Animesh (American Institute of Aeronautics and Astronautics Inc., 2019-01-06)
    Loss-of-Control events continue to be the most significant contributing factor to air accidents worldwide. Predictive systems capable of warning pilots of impending entry into control loss have the potential to further ...
  • Design, implementation and experimental testing of an inertial sensor system to quantify wing deflection 

    Schirmer, Georg; Steck, James E.; Chakravarthy, Animesh (American Institute of Aeronautics and Astronautics Inc., 2019-01-06)
    This research investigates a novel approach of using inertial micro-electromechanical sensors in combination with a Kalman state estimator to quantify wing deflection of a highly flexible morphing wing. Motivated by NASA’s ...
  • Adaptive control system for flapping wing aircraft: A gain study on optimal control modification 

    Chandrasekaran, Balaji K.; Steck, James E. (American Institute of Aeronautics and Astronautics, Inc., 2019-01-06)
    Prior work developed a model for a bird-like flapping wing aircraft using Modified strip theory for aerodynamics, a flight dynamics model based on Newtonian equations and an adaptive flight controller. This model was ...
  • Trajectory prediction using coupled cfd-rbd with dynamic meshing 

    Sathyanarayana, Nidhi D.; Hoffmann, Klaus A. (American Institute of Aeronautics and Astronautics, Inc., 2019-01-06)
    Debris released post bird impact can cause secondary damage to downwind airplane surfaces. The debris is simplified in geometry and represented as a flat plate. A coupled CFD-RBD solver with dynamic meshing is used for ...
  • Effect of data filtering on flight loads spectra 

    Rokhsaz, Kamran; Kliment, Linda K. (American Institute of Aeronautics and Astronautics, 2019-06-14)
    Operational data from 27.4 hours of aerial firefighting and ferry missions are used to examine the effect of various filters at removing the structural modes from the data and the corresponding effect on flight loads ...
  • Higher-order estimations of load factor from derived gust velocity 

    Rokhsaz, Kamran; Kliment, Linda K. (American Institute of Aeronautics and Astronautics, Inc., 2018-11-12)
    Pratt's formula, in which the aircraft is modeled as a single-degree-of-freedom system, is used extensively to extract derived gust velocities from measured normal acceleration. There is evidence that airframe mass ...
  • Stress model of composite pipe joints under bending 

    Yang, Chihdar Charles; Huang, Hai; Guan, Zhidong (SAGE Publications, 2002-06)
    Recently, composite pipe is becoming popular in the offshore oil and gas industry due to the new floating designs of various platforms which have made deepwater oil and gas exploration and production more economical and ...
  • A semi-analytical method for determining the strain energy release rate of cracks in adhesively-bonded single-lap composite joints 

    Yang, Chihdar Charles; Sun, Wenjun; Tomblin, John S.; Smeltzer, Stanley S., III (SAGE Publications, 2007-07)
    A semi-analytical method for determining the strain energy release rates due to a prescribed crack in an adhesively-bonded, single-lap composite joint subjected to axial tension is presented. The field equations in terms ...
  • Thermally induced loads of fastened hybrid composite/aluminum structures 

    Yang, Chihdar Charles; Sun, Wenjun; Seneviratne, Waruna; Shashidhar, Ananthram K. (American Institute of Aeronautics and Astronautics, 2008-03)
    Large composite structures have been increasingly used in the aviation industry. New applications of composite materials include primary structures such as aircraft fuselages. These large composite parts are sometimes ...
  • Evaluation and adjustments for ASTM D 5656 standard test method for thick-adherend metal lap-shear joints for determination of the stress-strain behavior of adhesives in shear by tension loading 

    Yang, Chihdar Charles; Huang, Hai; Tomblin, John S.; Oplinger, D.W (American Society for Testing and Materials, 2001-01)
    Adhesive-bonded joints have been used widely for composite materials as a necessary alternative to conventional mechanical joint designs. In a bonded joint, the load is transferred from one substrate to the other mainly ...
  • Characterization of bondline thickness effects in adhesive joints 

    Tomblin, John S.; Harter, P.; Seneviratne, Waruna; Yang, Chihdar Charles (American Society for Testing and Materials, 2002-04)
    Growing application of composite materials in air-frame structures tends to make significant use of bonded constructions. Despite the large work that has been done on adhesive characterization over previous years, various ...

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