The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform

Andrea Serrani - One of the best experts on this subject based on the ideXlab platform.

  • mach Flight Path Angle and yaw Angle commands
    2017
    Co-Authors: Andrea Serrani
    Abstract:

    This Simulink file contains the commands for Mach, FPA and Yaw to be provided to the reference models. Note that the step command for Mach must be initialized at 0 when used in the linear model and to the initial trim value mach0 when used with the nonlinear model. These command signals must be given as input to the second-order reference models.

  • adaptive restricted trajectory tracking for a non minimum phase hypersonic vehicle model
    Automatica, 2012
    Co-Authors: Lisa Fiorentini, Andrea Serrani
    Abstract:

    The design of a nonlinear robust controller for a non-minimum phase model of an air-breathing hypersonic vehicle is presented in this work. When Flight-Path Angle is selected as a regulated output and the elevator is the only control surface available for the pitch dynamics, longitudinal models of the rigid-body dynamics of air-breathing hypersonic vehicles exhibit unstable zero-dynamics that prevent the applicability of standard inversion methods for control design. The approach proposed in this paper uses a combination of small-gain arguments and adaptive control techniques for the design of a state-feedback controller that achieves asymptotic tracking of a family of velocity and Flight-Path Angle reference trajectories belonging to a given class of vehicle maneuvers, in spite of model uncertainties. The method reposes upon a suitable redefinition of the internal dynamics of a control-oriented model of the vehicle dynamics, and uses a time-scale separation between the controlled variables to manage the peaking phenomenon occurring in the system. Simulation results on a full nonlinear vehicle model that includes structural flexibility illustrate the effectiveness of the methodology.

  • robust nonlinear sequential loop closure control design for an air breathing hypersonic vehicle model
    American Control Conference, 2008
    Co-Authors: Lisa Fiorentini, Michael A Bolender, Andrea Serrani, David B. Doman
    Abstract:

    This paper describes the design of a nonlinear robust/adaptive controller for an air-breathing hypersonic vehicle model. Due to its complexity, a high fidelity model of the vehicle dynamics derived from first principles is used only in simulations, while a simplified model is adopted for control design. This control-oriented model retains most of the features of the high fidelity model, including non-minimum phase characteristic of the Flight-Path Angle dynamics and strong couplings between the engine and Flight dynamics, whereas flexibility effects are regarded as a dynamic perturbation. A nonlinear sequential loop-closure approach is adopted to design a dynamic state-feedback controller that provides stable tracking of velocity and altitude reference trajectories and allows to impose a desired trim value for the Angle of attack. Simulation results show that the proposed methodology achieves excellent tracking performances in spite of parameter uncertainties.

Qingdong Li - One of the best experts on this subject based on the ideXlab platform.

  • onboard planning of constrained longitudinal trajectory for reusable launch vehicles in terminal area
    Advances in Space Research, 2016
    Co-Authors: Zixuan Liang, Qingdong Li
    Abstract:

    Abstract A rapid planning algorithm is developed to generate a constrained longitudinal trajectory onboard for reusable launch vehicles (RLVs) in the terminal area energy management (TAEM) phase. The longitudinal trajectory is planned in the Flight-Path Angle vs. altitude space. This Flight-Path Angle profile is designed with required altitude, Flight-Path Angle and range-to-go, and then optimized as a one-parameter search problem to meet the velocity constraint. Considering the dynamic pressure constraint, a dynamic pressure protection (DPP) method is designed. With the DPP, the highly constrained longitudinal trajectory is generated by tracking the planned Flight-Path Angle profile. Finally, the TAEM trajectory planning algorithm is tested on the X-33 vehicle model in different cases. The algorithm is shown to be effective and robust to generate longitudinal Flight trajectories with all constraints satisfied in high precision. In each case, the constrained trajectory is planned within 1 s on a PC, which indicates that the algorithm is feasible to be employed onboard.

Tang Yimeng - One of the best experts on this subject based on the ideXlab platform.

  • design of the automatic terrain following system of aircraft based on fuzzy controller
    Computer Simulation, 2010
    Co-Authors: Tang Yimeng
    Abstract:

    The control law of automatic terrain following control system of modern aircraft is designed.First,the longitudinal model of aircraft is mainly studied by using the adaptive Angle method.Then,the fuzzy control law of automatic terrain following system is designed separately by controlling the Flight Path Angle and controlling the normal acceleration.Moreover,the simulation models are represented.The simulation results indicate that the control system designed is feasible and valid.In the end,the output of the Path Angle is taken for an example to illustrate that,compared with the traditional PID control system,the fuzzy control system is normally more stable.

John Deyst - One of the best experts on this subject based on the ideXlab platform.

  • preliminary Flight tests of pseudo attitude using single antenna gps sensing
    Document Analysis Systems, 1998
    Co-Authors: Richard P. Kornfeld, R J Hansman, John Deyst
    Abstract:

    This paper describes a novel method for aircraft control based on pseudo-attitude. The pseudo-attitude information consists of Flight Path Angle and pseudo-roll Angle about the aircraft velocity vector axis and is completely observable from single antenna GPS velocity measurements. Pseudo-attitude information is presented on a pseudo-attitude display which shows Flight Path Angle and pseudo-roll Angle instead of the traditional pitch and roll information, thus yielding direct indications of the actual Flight Path state. Flight tests in a Piper Arrow aircraft showed that pseudo-attitude is equivalent in performance to conventional attitude, with no subjective or objective differences between them. Possible applications of pseudo-attitude include its use as a backup attitude system, in guidance display or Flight control schemes or for fault diagnostics in redundant systems.

  • single antenna gps based aircraft attitude determination
    Annual of Navigation, 1998
    Co-Authors: Richard P. Kornfeld, John R Hansman, John Deyst
    Abstract:

    A method for synthesizing aircraft attitude information from single-antenna GPS velocity measurements is described. The attitude information consists of Flight Path Angle and roll Angle about the aircraft velocity vector axis. This ‘pseudo-attitude’ is compared with the conventional attitude consisting of pitch and roll Angle about the body axis. In addition, a pseudo-attitude display is presented that shows Flight Path Angle and roll Angle instead of the traditional pitch and roll information, thus yielding direct indications of the actual Flight Path state. Flight tests in a Piper Arrow aircraft demonstrated that pseudo-attitude is equivalent in performance to conventional attitude, with no subjective or objective differences between the two. The results show that a single-antenna GPS receiver provides a useful source of attitude information and consequently may be used as a backup attitude system or for fault diagnostics in redundant systems.

Zixuan Liang - One of the best experts on this subject based on the ideXlab platform.

  • onboard planning of constrained longitudinal trajectory for reusable launch vehicles in terminal area
    Advances in Space Research, 2016
    Co-Authors: Zixuan Liang, Qingdong Li
    Abstract:

    Abstract A rapid planning algorithm is developed to generate a constrained longitudinal trajectory onboard for reusable launch vehicles (RLVs) in the terminal area energy management (TAEM) phase. The longitudinal trajectory is planned in the Flight-Path Angle vs. altitude space. This Flight-Path Angle profile is designed with required altitude, Flight-Path Angle and range-to-go, and then optimized as a one-parameter search problem to meet the velocity constraint. Considering the dynamic pressure constraint, a dynamic pressure protection (DPP) method is designed. With the DPP, the highly constrained longitudinal trajectory is generated by tracking the planned Flight-Path Angle profile. Finally, the TAEM trajectory planning algorithm is tested on the X-33 vehicle model in different cases. The algorithm is shown to be effective and robust to generate longitudinal Flight trajectories with all constraints satisfied in high precision. In each case, the constrained trajectory is planned within 1 s on a PC, which indicates that the algorithm is feasible to be employed onboard.