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Frederick H. Lutze - One of the best experts on this subject based on the ideXlab platform.

  • significance of the Dihedral Effect in rapid fuselage reorientation maneuvers
    Journal of Aircraft, 1994
    Co-Authors: Spiro Bocvarov, Eugene M. Cliff, Frederick H. Lutze
    Abstract:

    A study is presented about the role the Dihedral Effect (rolling moment due to sideslip) can have in fuselagereorientation maneuvers that involve high angles of attack. A mathematical model for attitude maneuvers is developed, which accurately represents the High Angle-of-Attack Research Vehicle, including propulsive moments generated by thrust-vector ing. The fuselage-reorientation problem is posed as an unconstrained timeoptimal control problem, and numerical extremal trajectories are obtained. These trajectories are examined in order to determine if and when the Dihedral Effect contributes significantly to the maneuvers. Results indicate that for most reorientation maneuvers the Dihedral Effect is small, and that these minimum-time trajectories occur with small sideslip angles. ARIOUS technological advances have enabled the development of a new generation of combat aircraft, with expanded flight envelope and improved maneuvering capabilities (supermaneuverable aircraft 1"4). These aircraft will be more "agile" and have the ability to operate at extreme angles of attack. One of the enabling technologies is the concept of propulsive control-moments,5-6 generated by thrustvectoring (TV). At higher angles of attack, where the aerodynamic control surfaces are less Effective, TV can be used for attitude control, while at lower angles of attack the propulsive control-moments can supplement the aerodynamic control surfaces. In order to gain a tactical advantage in a combat situation, it is desirable to perform the combat maneuvers in minimum time. Modern computers and advanced numerical techniques, along with the accurate aircraft aerodynamic models obtained from wind-tunnel measurements, facilitate numerical study of the problem of optimal tactical maneuvering. The authors have recently reported7 mathematical model for the High Angle-of-Attack Research Vehicle9 (HARV), developed for study of time-optimal fuselage-reorientation maneuvering problems. The model neglects the translational motion of the aircraft (therefore being valid only for rapid attitude maneuvers, during which the aircraft velocity-vector does not change significantly). Results obtained with this model can be used as a starting point for a 6-degree-of-fr eedom model and more complex tactical-maneuvering optimal control problems. In performing minimum-time reorientation maneuvers, one might expect that the use of sideslip to create rolling moment (Dihedral Effect) might be a useful means to reduce the maneuvering time. In this article we look at this possibility in detail, and show that for a large class of reorientation maneuvers of practical interest and tactical significance the di

  • Significance of the Dihedral Effect in rapid fuselage-reorientation maneuvers
    Journal of Aircraft, 1994
    Co-Authors: Spiro Bocvarov, Eugene M. Cliff, Frederick H. Lutze
    Abstract:

    A study is presented about the role the Dihedral Effect (rolling moment due to sideslip) can have in fuselagereorientation maneuvers that involve high angles of attack. A mathematical model for attitude maneuvers is developed, which accurately represents the High Angle-of-Attack Research Vehicle, including propulsive moments generated by thrust-vector ing. The fuselage-reorientation problem is posed as an unconstrained timeoptimal control problem, and numerical extremal trajectories are obtained. These trajectories are examined in order to determine if and when the Dihedral Effect contributes significantly to the maneuvers. Results indicate that for most reorientation maneuvers the Dihedral Effect is small, and that these minimum-time trajectories occur with small sideslip angles. ARIOUS technological advances have enabled the development of a new generation of combat aircraft, with expanded flight envelope and improved maneuvering capabilities (supermaneuverable aircraft 1"4). These aircraft will be more "agile" and have the ability to operate at extreme angles of attack. One of the enabling technologies is the concept of propulsive control-moments,5-6 generated by thrustvectoring (TV). At higher angles of attack, where the aerodynamic control surfaces are less Effective, TV can be used for attitude control, while at lower angles of attack the propulsive control-moments can supplement the aerodynamic control surfaces. In order to gain a tactical advantage in a combat situation, it is desirable to perform the combat maneuvers in minimum time. Modern computers and advanced numerical techniques, along with the accurate aircraft aerodynamic models obtained from wind-tunnel measurements, facilitate numerical study of the problem of optimal tactical maneuvering. The authors have recently reported7

  • Significance of the Dihedral-Effect for a combat aircraft in rapid fuselage-reorientation maneuvers
    Astrodynamics Conference, 1992
    Co-Authors: Spiro Bocvarov, Eugene M. Cliff, Frederick H. Lutze
    Abstract:

    In the quest for understanding problems of supermaneuverability for combat aircraft, a study is presented about the role the Dihedral-Effect can have in fuselage-reorientation maneuvers that involve high angles of attack. A mathematical model for attitude maneuvers is developed, which accurately represents the High Angle-of-Attack Research Vehicle, including thrust-vectoring generated propulsive moments. The fuselage-reorientation problem is posed as an unconstrained time-optimal control problem. Results for a few families of extremal trajectories are obtained, and the global role of the Dihedral Effect in the course of the corresponding maneuvers is discussed. In addition, a detailed case-study is presented for an extremal trajectory which utilizes the Dihedral Effect with considerable benefit.

Spiro Bocvarov - One of the best experts on this subject based on the ideXlab platform.

  • significance of the Dihedral Effect in rapid fuselage reorientation maneuvers
    Journal of Aircraft, 1994
    Co-Authors: Spiro Bocvarov, Eugene M. Cliff, Frederick H. Lutze
    Abstract:

    A study is presented about the role the Dihedral Effect (rolling moment due to sideslip) can have in fuselagereorientation maneuvers that involve high angles of attack. A mathematical model for attitude maneuvers is developed, which accurately represents the High Angle-of-Attack Research Vehicle, including propulsive moments generated by thrust-vector ing. The fuselage-reorientation problem is posed as an unconstrained timeoptimal control problem, and numerical extremal trajectories are obtained. These trajectories are examined in order to determine if and when the Dihedral Effect contributes significantly to the maneuvers. Results indicate that for most reorientation maneuvers the Dihedral Effect is small, and that these minimum-time trajectories occur with small sideslip angles. ARIOUS technological advances have enabled the development of a new generation of combat aircraft, with expanded flight envelope and improved maneuvering capabilities (supermaneuverable aircraft 1"4). These aircraft will be more "agile" and have the ability to operate at extreme angles of attack. One of the enabling technologies is the concept of propulsive control-moments,5-6 generated by thrustvectoring (TV). At higher angles of attack, where the aerodynamic control surfaces are less Effective, TV can be used for attitude control, while at lower angles of attack the propulsive control-moments can supplement the aerodynamic control surfaces. In order to gain a tactical advantage in a combat situation, it is desirable to perform the combat maneuvers in minimum time. Modern computers and advanced numerical techniques, along with the accurate aircraft aerodynamic models obtained from wind-tunnel measurements, facilitate numerical study of the problem of optimal tactical maneuvering. The authors have recently reported7 mathematical model for the High Angle-of-Attack Research Vehicle9 (HARV), developed for study of time-optimal fuselage-reorientation maneuvering problems. The model neglects the translational motion of the aircraft (therefore being valid only for rapid attitude maneuvers, during which the aircraft velocity-vector does not change significantly). Results obtained with this model can be used as a starting point for a 6-degree-of-fr eedom model and more complex tactical-maneuvering optimal control problems. In performing minimum-time reorientation maneuvers, one might expect that the use of sideslip to create rolling moment (Dihedral Effect) might be a useful means to reduce the maneuvering time. In this article we look at this possibility in detail, and show that for a large class of reorientation maneuvers of practical interest and tactical significance the di

  • Significance of the Dihedral Effect in rapid fuselage-reorientation maneuvers
    Journal of Aircraft, 1994
    Co-Authors: Spiro Bocvarov, Eugene M. Cliff, Frederick H. Lutze
    Abstract:

    A study is presented about the role the Dihedral Effect (rolling moment due to sideslip) can have in fuselagereorientation maneuvers that involve high angles of attack. A mathematical model for attitude maneuvers is developed, which accurately represents the High Angle-of-Attack Research Vehicle, including propulsive moments generated by thrust-vector ing. The fuselage-reorientation problem is posed as an unconstrained timeoptimal control problem, and numerical extremal trajectories are obtained. These trajectories are examined in order to determine if and when the Dihedral Effect contributes significantly to the maneuvers. Results indicate that for most reorientation maneuvers the Dihedral Effect is small, and that these minimum-time trajectories occur with small sideslip angles. ARIOUS technological advances have enabled the development of a new generation of combat aircraft, with expanded flight envelope and improved maneuvering capabilities (supermaneuverable aircraft 1"4). These aircraft will be more "agile" and have the ability to operate at extreme angles of attack. One of the enabling technologies is the concept of propulsive control-moments,5-6 generated by thrustvectoring (TV). At higher angles of attack, where the aerodynamic control surfaces are less Effective, TV can be used for attitude control, while at lower angles of attack the propulsive control-moments can supplement the aerodynamic control surfaces. In order to gain a tactical advantage in a combat situation, it is desirable to perform the combat maneuvers in minimum time. Modern computers and advanced numerical techniques, along with the accurate aircraft aerodynamic models obtained from wind-tunnel measurements, facilitate numerical study of the problem of optimal tactical maneuvering. The authors have recently reported7

  • Significance of the Dihedral-Effect for a combat aircraft in rapid fuselage-reorientation maneuvers
    Astrodynamics Conference, 1992
    Co-Authors: Spiro Bocvarov, Eugene M. Cliff, Frederick H. Lutze
    Abstract:

    In the quest for understanding problems of supermaneuverability for combat aircraft, a study is presented about the role the Dihedral-Effect can have in fuselage-reorientation maneuvers that involve high angles of attack. A mathematical model for attitude maneuvers is developed, which accurately represents the High Angle-of-Attack Research Vehicle, including thrust-vectoring generated propulsive moments. The fuselage-reorientation problem is posed as an unconstrained time-optimal control problem. Results for a few families of extremal trajectories are obtained, and the global role of the Dihedral Effect in the course of the corresponding maneuvers is discussed. In addition, a detailed case-study is presented for an extremal trajectory which utilizes the Dihedral Effect with considerable benefit.

Eugene M. Cliff - One of the best experts on this subject based on the ideXlab platform.

  • significance of the Dihedral Effect in rapid fuselage reorientation maneuvers
    Journal of Aircraft, 1994
    Co-Authors: Spiro Bocvarov, Eugene M. Cliff, Frederick H. Lutze
    Abstract:

    A study is presented about the role the Dihedral Effect (rolling moment due to sideslip) can have in fuselagereorientation maneuvers that involve high angles of attack. A mathematical model for attitude maneuvers is developed, which accurately represents the High Angle-of-Attack Research Vehicle, including propulsive moments generated by thrust-vector ing. The fuselage-reorientation problem is posed as an unconstrained timeoptimal control problem, and numerical extremal trajectories are obtained. These trajectories are examined in order to determine if and when the Dihedral Effect contributes significantly to the maneuvers. Results indicate that for most reorientation maneuvers the Dihedral Effect is small, and that these minimum-time trajectories occur with small sideslip angles. ARIOUS technological advances have enabled the development of a new generation of combat aircraft, with expanded flight envelope and improved maneuvering capabilities (supermaneuverable aircraft 1"4). These aircraft will be more "agile" and have the ability to operate at extreme angles of attack. One of the enabling technologies is the concept of propulsive control-moments,5-6 generated by thrustvectoring (TV). At higher angles of attack, where the aerodynamic control surfaces are less Effective, TV can be used for attitude control, while at lower angles of attack the propulsive control-moments can supplement the aerodynamic control surfaces. In order to gain a tactical advantage in a combat situation, it is desirable to perform the combat maneuvers in minimum time. Modern computers and advanced numerical techniques, along with the accurate aircraft aerodynamic models obtained from wind-tunnel measurements, facilitate numerical study of the problem of optimal tactical maneuvering. The authors have recently reported7 mathematical model for the High Angle-of-Attack Research Vehicle9 (HARV), developed for study of time-optimal fuselage-reorientation maneuvering problems. The model neglects the translational motion of the aircraft (therefore being valid only for rapid attitude maneuvers, during which the aircraft velocity-vector does not change significantly). Results obtained with this model can be used as a starting point for a 6-degree-of-fr eedom model and more complex tactical-maneuvering optimal control problems. In performing minimum-time reorientation maneuvers, one might expect that the use of sideslip to create rolling moment (Dihedral Effect) might be a useful means to reduce the maneuvering time. In this article we look at this possibility in detail, and show that for a large class of reorientation maneuvers of practical interest and tactical significance the di

  • Significance of the Dihedral Effect in rapid fuselage-reorientation maneuvers
    Journal of Aircraft, 1994
    Co-Authors: Spiro Bocvarov, Eugene M. Cliff, Frederick H. Lutze
    Abstract:

    A study is presented about the role the Dihedral Effect (rolling moment due to sideslip) can have in fuselagereorientation maneuvers that involve high angles of attack. A mathematical model for attitude maneuvers is developed, which accurately represents the High Angle-of-Attack Research Vehicle, including propulsive moments generated by thrust-vector ing. The fuselage-reorientation problem is posed as an unconstrained timeoptimal control problem, and numerical extremal trajectories are obtained. These trajectories are examined in order to determine if and when the Dihedral Effect contributes significantly to the maneuvers. Results indicate that for most reorientation maneuvers the Dihedral Effect is small, and that these minimum-time trajectories occur with small sideslip angles. ARIOUS technological advances have enabled the development of a new generation of combat aircraft, with expanded flight envelope and improved maneuvering capabilities (supermaneuverable aircraft 1"4). These aircraft will be more "agile" and have the ability to operate at extreme angles of attack. One of the enabling technologies is the concept of propulsive control-moments,5-6 generated by thrustvectoring (TV). At higher angles of attack, where the aerodynamic control surfaces are less Effective, TV can be used for attitude control, while at lower angles of attack the propulsive control-moments can supplement the aerodynamic control surfaces. In order to gain a tactical advantage in a combat situation, it is desirable to perform the combat maneuvers in minimum time. Modern computers and advanced numerical techniques, along with the accurate aircraft aerodynamic models obtained from wind-tunnel measurements, facilitate numerical study of the problem of optimal tactical maneuvering. The authors have recently reported7

  • Significance of the Dihedral-Effect for a combat aircraft in rapid fuselage-reorientation maneuvers
    Astrodynamics Conference, 1992
    Co-Authors: Spiro Bocvarov, Eugene M. Cliff, Frederick H. Lutze
    Abstract:

    In the quest for understanding problems of supermaneuverability for combat aircraft, a study is presented about the role the Dihedral-Effect can have in fuselage-reorientation maneuvers that involve high angles of attack. A mathematical model for attitude maneuvers is developed, which accurately represents the High Angle-of-Attack Research Vehicle, including thrust-vectoring generated propulsive moments. The fuselage-reorientation problem is posed as an unconstrained time-optimal control problem. Results for a few families of extremal trajectories are obtained, and the global role of the Dihedral Effect in the course of the corresponding maneuvers is discussed. In addition, a detailed case-study is presented for an extremal trajectory which utilizes the Dihedral Effect with considerable benefit.

C.-y. Chiang - One of the best experts on this subject based on the ideXlab platform.

  • H/sub /spl infin// control of crippled aircraft in lateral motion with throttles only
    Proceedings of 35th IEEE Conference on Decision and Control, 1
    Co-Authors: Edmond A. Jonckheere, C.-y. Chiang
    Abstract:

    In a hydraulic failure emergency situation, throttles can be used to augment or replace the aircraft hydraulically-actuated flight control system. Collective throttle inputs can be used to control pitch. Differential throttle inputs generate yaw, which through Dihedral Effect result in roll. In this paper we design a controller for crippled airplanes in lateral motion. Through the H/sub /spl infin// compensator, the response of the crippled airplane, using throttles as the only control inputs, matches optimally in the H/sub /spl infin// sense the response of the normal airplane to control surface command signals.

Etienne Everaere - One of the best experts on this subject based on the ideXlab platform.

  • Improvement of SAR/ISAR simulation in MOCEM V4.5 by computation of the ship's Bow wave
    2019
    Co-Authors: Corentin Le Barbu, Christian Cochin, Etienne Everaere
    Abstract:

    In DGA tool MOCEM, ship signature of a moving ship takes into account several coupling Effects such as the Dihedral Effect between the sea and the hull or the kelvin wakes. But in airborne SAR/ISAR images, we can sometime observe a Doppler spreading that generates a defocusing phenomenon at the bow of the ship that is associated to the bow wave. Here we present the improvements done on the simulation to reproduce this Effect.

  • Improvement of SAR/ISAR simulation in MOCEM V4.5 by computation of the ship Bow wave
    2019 International Radar Conference (RADAR), 2019
    Co-Authors: Corentin Le Barbu, Christian Cochin, Etienne Everaere
    Abstract:

    In the DGA simulation software MOCEM, signature of a moving ship takes into account several coupling Effects such as the Dihedral Effect between the sea and the hull or the kelvin wakes. But in airborne SAR/ISAR images, we sometimes observe a Doppler spreading that generates a defocusing phenomenon at the bow of the ship, associated to the bow wave. Here we present the improvements done on the simulation to reproduce this Effect.