The Experts below are selected from a list of 11148 Experts worldwide ranked by ideXlab platform

Chang-yin Sun - One of the best experts on this subject based on the ideXlab platform.

  • Fast sliding mode control on air-breathing Hypersonic Vehicles with transient response analysis:
    Proceedings of the Institution of Mechanical Engineers Part I: Journal of Systems and Control Engineering, 2015
    Co-Authors: Mu Chaoxu, Chang-yin Sun
    Abstract:

    This article studies the tracking control of air-breathing Hypersonic Vehicles to the reference velocity and the reference altitude with a fast non-linear sliding mode control scheme. By the feedback linearization technology, the longitudinal model of air-breathing Hypersonic Vehicles is divided into the velocity subsystem and the altitude subsystem. Two lumped tracking error variables are developed based on velocity and altitude subsystems, and non-singular terminal sliding mode control is used so that the two lumped error variables converge to the origin in finite time. During the tracking process, transient properties of non-singular terminal sliding mode control are investigated from the mathematical and theoretical standpoint. The simulation results have shown that the fast non-linear sliding mode control is effective for the tracking control of air-breathing Hypersonic Vehicles and have demonstrated that the relevant transient response analysis is correct.

  • adaptive nonsingular terminal sliding mode control design for near space Hypersonic Vehicles
    IEEE CAA Journal of Automatica Sinica, 2014
    Co-Authors: Ruimin Zhang, Lu Dong, Chang-yin Sun
    Abstract:

    This paper presents an adaptive nonsingular terminal sliding mode approach for the attitude control of near space Hypersonic Vehicles (NSHV) in the presence of parameter uncertainties and external disturbances. Firstly, a novel nonsingular terminal sliding surface is developed and its finite-time convergence is analyzed. Then, an adaptive nonsingular terminal sliding mode control law is proposed, which is chattering free. In the proposed approach, all parameter uncertainties and external disturbances are lumped into one term, which is estimated by an adaptive uncertainty estimation for eliminating the boundary requirement needed in the conventional control design. Subsequently, stability of the closed-loop system is proven based on Lyapunov theory. Finally, the proposed approach is applied to the attitude control design for NSHV. Simulation results show that the proposed approach attains a satisfactory performance in the presence of parameter uncertainties and external disturbances.

  • nonlinear disturbance observer based robust flight control for airbreathing Hypersonic Vehicles
    IEEE Transactions on Aerospace and Electronic Systems, 2013
    Co-Authors: Jun Yang, Chang-yin Sun, Lei Guo
    Abstract:

    The work presented here is concerned with the robust flight control problem for the longitudinal dynamics of a generic airbreathing Hypersonic Vehicles (AHVs) under mismatched disturbances via a nonlinear-disturbance-observer-based control (NDOBC) method. Compared with other robust flight control method for AHV, the proposed method obtains not only promising robustness and disturbance rejection performance but also the property of nominal performance recovery. The merits of the proposed method are validated by simulation studies.

  • Some Control Problems for Near Space Hypersonic Vehicles
    Acta Automatica Sinica, 2013
    Co-Authors: Chang-yin Sun
    Abstract:

    The characteristics of near space Hypersonic Vehicles have brought about new difculty in modeling and control. Firstly, this paper analyzes some characteristics of Hypersonic Vehicles, and then puts forward the unified model in the large envelope flight. Secondly, an overview of current control studies on the cruising phase and the reentry phase is presented, where the problems of flexibility, non-minimum phase, integrated design of reentry guidance and control are emphasized. Finally, with the development of Hypersonic Vehicles, the interception issue of Hypersonic targets is discussed,which provides the potentiality for future research.

Michael Keidar - One of the best experts on this subject based on the ideXlab platform.

  • Modeling Radio Communication Blackout and Blackout Mitigation in Hypersonic Vehicles
    Journal of Spacecraft and Rockets, 2015
    Co-Authors: Madhusudhan Kundrapu, John Loverich, Kristian Beckwith, Peter Stoltz, Alexey Shashurin, Michael Keidar
    Abstract:

    A procedure for the modeling and analysis of radio communication blackout of Hypersonic Vehicles is presented. The weakly ionized plasma generated around the surface of a Hypersonic reentry vehicle is simulated using full Navier–Stokes equations in multispecies single fluid form. A seven-species air chemistry model is used to compute the individual species densities in air including ionization: plasma densities are compared with the experiment. The electromagnetic wave’s interaction with the plasma layer is modeled using multifluid equations for fluid transport and full Maxwell’s equations for the electromagnetic fields. The multifluid solver is verified for a whistler wave propagating through a slab. First principles radio communication blackout over a Hypersonic vehicle is demonstrated along with a simple blackout mitigation scheme using a magnetic window.

  • Modeling radio communication blackout and blackout mitigation in Hypersonic Vehicles
    arXiv: Computational Physics, 2014
    Co-Authors: Madhusudhan Kundrapu, John Loverich, Kristian Beckwith, Peter Stoltz, Alexey Shashurin, Michael Keidar
    Abstract:

    A procedure for the modeling and analysis of radio communication blackout of Hypersonic Vehicles is presented. The weakly ionized plasma generated around the surface of a Hypersonic reentry vehicle is simulated using full Navier-Stokes equations in multi-species single fluid form. A seven species air chemistry model is used to compute the individual species densities in air including ionization - plasma densities are compared with experiment. The electromagnetic wave's interaction with the plasma layer is modeled using multi-fluid equations for fluid transport and full Maxwell's equations for the electromagnetic fields. The multi-fluid solver is verified for a whistler wave propagating through a slab. First principles radio communication blackout over a Hypersonic vehicle is demonstrated along with a simple blackout mitigation scheme using a magnetic window.

Zhen Liu - One of the best experts on this subject based on the ideXlab platform.

  • adaptive fuzzy nonsmooth backstepping output feedback control for Hypersonic Vehicles with finite time convergence
    IEEE Transactions on Fuzzy Systems, 2020
    Co-Authors: Jinlin Sun, Zhen Liu
    Abstract:

    It is commonly believed that uncertainties are obstacles to the tracking performances of flexible air-breathing Hypersonic Vehicles (FAHVs). In addition, the estimation of unmeasured states in an FAHV makes this issue much more complicated. To deal with these difficulties, this article explores a novel adaptive fuzzy nonsmooth backstepping output-feedback control scheme for the FAHV with closed-loop finite-time convergence. First, to approximate the unknown dynamics of the FAHV, some function approximators are constructed by utilizing an interval type-2 (IT2) fuzzy logic system. On this basis, a fixed-time convergent adaptive IT2 fuzzy observer is designed to estimate the unmeasured flight path angle and the unmeasured angle of attack of the FAHV accurately and rapidly. Consequently, the estimation errors of the designed observer are convergent in a fixed time independent of their initial estimation errors. Furthermore, based on the estimated states, velocity and altitude tracking controllers are designed by using a finite-time adaptive IT2 fuzzy nonsmooth backstepping control technique, which avoids the problem of “explosion of complexity” in traditional backstepping methods. Subsequently, rigorous Lyapunov stability analysis is conducted to show the finite-time convergence of the closed-loop signals of the FAHV control system. Finally, the robustness and superiority of the proposed control scheme is validated by several simulations in representative scenarios.

  • fixed time control with uncertainty and measurement noise suppression for Hypersonic Vehicles via augmented sliding mode observers
    IEEE Transactions on Industrial Informatics, 2020
    Co-Authors: Jinlin Sun, Zhen Liu
    Abstract:

    Uncertainty and measurement noise are main obstacles that limit the tracking control performances of flexible air-breathing Hypersonic Vehicles (FAHVs). In this article, we propose a novel fixed-time convergent nonsmooth backstepping control scheme for FAHV via augmented sliding mode observers (ASMOs) to overcome these obstacles. The ASMOs are first designed for the FAHV dynamics by employing the measured states corrupted by noises as inputs. On one hand, the ASMOs can simultaneously estimate the uncertainties and filter out the measurement noises. On the other hand, the observation error of each ASMO can be convergent within a fixed time independent of its initial observation error. Then, based on the estimation results, the altitude and velocity tracking controllers are developed by using fixed-time nonsmooth backstepping technique. Afterwards, a Lyapunov-based stability analysis is given to illustrate the fixed-time convergence of the closed-loop signals of the FAHV control system. Finally, comparative simulations are conducted to illustrate the superiority of the proposed control scheme.

  • immersion and invariance adaptive finite time control of air breathing Hypersonic Vehicles
    Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering, 2019
    Co-Authors: Chao Han, Zhen Liu
    Abstract:

    In this paper, a novel adaptive finite-time control of air-breathing Hypersonic Vehicles is proposed. Based on the immersion and invariance theory, an adaptive finite-time control method for general second-order systems is first derived, using nonsingular terminal sliding mode scheme. Then the method is applied to the control system design of a flexible air-breathing vehicle model, whose dynamics can be decoupled into first-order and second-order subsystems by time-scale separation principle. The main features of this Hypersonic vehicle control system lie in the design flexibility of the parameter adaptive laws and the rapid convergence to the equilibrium point. Finally, simulations are conducted, which demonstrate that the control system has the features of fast and accurate tracking to command trajectories and strong robustness to parametric and non-parametric uncertainties.

  • an overview of waverider design concept in airframe inlet integration methodology for air breathing Hypersonic Vehicles
    Acta Astronautica, 2018
    Co-Authors: Feng Ding, Jun Liu, Chibing Shen, Wei Huang, Zhen Liu, Shaohua Chen
    Abstract:

    Abstract A waverider is any supersonic or Hypersonic lifting body that is characterized by an attached, or nearly attached, bow shock wave along its leading edge. A waverider can possess high lift-to-drag ratio characteristics as well as an ideal precompression surface of the inlet system, and hence has become one of the most promising designs for air-breathing Hypersonic Vehicles. Two classes of general methodologies exist for using the waverider concept in the airframe/inlet integration for air-breathing Hypersonic Vehicles. In the first class, the waverider is used only as the forebody of a vehicle, and behaves as the precompression surface to efficiently provide the inlet system with the required compression flow field. In the second class, and to take advantage of the waverider's high lift-to-drag ratio characteristics as well as the ideal precompression surface for the engine, the waverider design is used as the basis for the design of the entire vehicle, and the engine is generated within the pristine waverider definition while maintaining the bow shock wave attaching to the leading edge. In this paper, waverider applications developed by domestic and overseas scholars in the airframe/inlet integration methodology for air-breathing Hypersonic Vehicles are reviewed and classified, and the future research and development trends are presented. The idea for the design of a waverider-derived air-breathing Hypersonic vehicle can be summarized as follows: the modeling of the basic flow is used to design the waverider in the streamwise direction, and the osculating theory is used to design the waverider in the spanwise direction.

  • adaptive interval type 2 fuzzy output feedback control based on nonlinear high gain observer for flexible air breathing Hypersonic Vehicles
    Youth Academic Annual Conference of Chinese Association of Automation, 2017
    Co-Authors: Xinlong Tao, Ruyi Yuan, Zhen Liu
    Abstract:

    In this paper, an adaptive interval type-2 fuzzy output feedback control (AIT2-FOFC) scheme is developed for flexible air-breathing Hypersonic Vehicles (FAHVs) in the presence of unknown flexible dynamics and parameter uncertainties. After calculating the derivatives of the velocity and altitude repeatedly, a state feedback dynamic inversion controller is formulated as the basic nominal controller. Then, an adaptive interval type-2 fuzzy logic system (AIT2-FLS) is constructed to approximate the unknown uncertainties in the FAHV longitudinal model. Furthermore, a nonlinear high gain observer is designed to estimate the high order derivatives of the velocity tracking error and altitude tracking error which are unavailable in practice. Based on the separation principle, the overall AIT2-FOFC scheme is finally obtained through combining the state feedback controller and the nonlinear high gain observer. Simulation at last demonstrates the effectiveness of our proposed control scheme.

Iain D. Boyd - One of the best experts on this subject based on the ideXlab platform.

  • plasma assisted cooling of hot surfaces on Hypersonic Vehicles
    Frontiers in Physics, 2019
    Co-Authors: Kyle M Hanquist, Iain D. Boyd
    Abstract:

    Electron transpiration cooling (ETC) is a proposed thermal management approach for the leading edges of Hypersonic Vehicles that utilizes thermionic emission to emit electrons to carry heat away from the surface. A modeling approach for assessing ETC in a computational fluid dynamics (CFD) framework and is evaluated using previously completed experiments. The modeling approach is presented includes developing boundary conditions to account for space-charge-limited emission to accurately determine the level of electron emission from the surface. The effectiveness of ETC for multiple test cases are investigated including sharp leading edges and blunt bodies. For each of these test cases, ETC affects the surface properties, most notably the surface temperature, suggesting that ETC occurs for bodies in thermally intense, ionized flows, no matter the shape of the leading edge. An approximate approach is also presented to assess ETC in an ionized flow and compares its cooling power to radiative cooling.

  • Aerothermodynamic Design Optimization of Hypersonic Vehicles
    Journal of Thermophysics and Heat Transfer, 2019
    Co-Authors: Sinan Eyi, Kyle M Hanquist, Iain D. Boyd
    Abstract:

    The objective of this study is to develop a reliable and efficient design optimization method for Hypersonic Vehicles focused on aerothermodynamic environments. Considering the nature of Hypersonic...

  • detailed modeling of electron emission for transpiration cooling of Hypersonic Vehicles
    Journal of Applied Physics, 2017
    Co-Authors: Kyle M Hanquist, Kentaro Hara, Iain D. Boyd
    Abstract:

    Electron transpiration cooling (ETC) is a recently proposed approach to manage the high heating loads experienced at the sharp leading edges of Hypersonic Vehicles. Computational fluid dynamics (CFD) can be used to investigate the feasibility of ETC in a Hypersonic environment. A modeling approach is presented for ETC, which includes developing the boundary conditions for electron emission from the surface, accounting for the space-charge limit effects of the near-wall plasma sheath. The space-charge limit models are assessed using 1D direct-kinetic plasma sheath simulations, taking into account the thermionically emitted electrons from the surface. The simulations agree well with the space-charge limit theory proposed by Takamura et al. for emitted electrons with a finite temperature, especially at low values of wall bias, which validates the use of the theoretical model for the Hypersonic CFD code. The CFD code with the analytical sheath models is then used for a test case typical of a leading edge radi...

  • conceptual analysis of electron transpiration cooling for the leading edges of Hypersonic Vehicles
    AIAA AVIATION 2014 -11th AIAA ASME Joint Thermophysics and Heat Transfer Conference 2014, 2014
    Co-Authors: Hicham Alkandry, Kyle M Hanquist, Iain D. Boyd
    Abstract:

    Recent progress is presented in an ongoing effort to perform a conceptual analysis of possible electron transpiration cooling using thermo-electric materials at the leading edges of Hypersonic Vehicles. The implementation of a new boundary condition in the CFD code LeMANS to model the thermionic emission of electrons from the leading edges of Hypersonic Vehicles is described. A parametric study is performed to understand the effects of the material work function, the freestream velocity, and the leading edge geometry on this cooling effect. The numerical results reveal that lower material work functions, higher freestream velocities, and smaller leading edges can increase the cooling effect due to larger emission current densities. The numerical results also show that the electric field produced by the electron emission may not have a significant effect on the predicted properties. Future work recommendations are provided that may improve the physical accuracy of the modeling capabilities used in this study.

Jinlin Sun - One of the best experts on this subject based on the ideXlab platform.

  • fixed time sliding mode disturbance observer based nonsmooth backstepping control for Hypersonic Vehicles
    IEEE Transactions on Systems Man and Cybernetics, 2020
    Co-Authors: Jinlin Sun, Xiangmin Tan
    Abstract:

    This paper presents a novel fixed-time sliding mode disturbance observer (SMDO)-based robust backstepping cruise tracking control scheme with closed-loop finite-time convergence for flexible air-breathing Hypersonic Vehicles (FAHVs). In order to enhance the control system’s robustness, a fixed-time SMDO is designed to compensate for the flexibility effects, model uncertainties, and external disturbances in FAHVs. In consequence, fixed convergence time of disturbance observation is achieved independently of initial estimation errors. Furthermore, velocity and altitude continuous finite-time tracking controllers are constructed by incorporating the SMDO and nonsmooth backstepping technique. To solve the problem of “explosion of complexity” in the conventional backstepping approach, nonsmooth filters are specifically constructed to generate the derivatives of virtual control laws. A Lyapunov-based stability analysis is conducted to show the finite-time convergence of the closed-loop FAHV control system. Finally, several representative numerical simulations are given to illustrate the effectiveness and superiority of the proposed control strategy.

  • adaptive fuzzy nonsmooth backstepping output feedback control for Hypersonic Vehicles with finite time convergence
    IEEE Transactions on Fuzzy Systems, 2020
    Co-Authors: Jinlin Sun, Zhen Liu
    Abstract:

    It is commonly believed that uncertainties are obstacles to the tracking performances of flexible air-breathing Hypersonic Vehicles (FAHVs). In addition, the estimation of unmeasured states in an FAHV makes this issue much more complicated. To deal with these difficulties, this article explores a novel adaptive fuzzy nonsmooth backstepping output-feedback control scheme for the FAHV with closed-loop finite-time convergence. First, to approximate the unknown dynamics of the FAHV, some function approximators are constructed by utilizing an interval type-2 (IT2) fuzzy logic system. On this basis, a fixed-time convergent adaptive IT2 fuzzy observer is designed to estimate the unmeasured flight path angle and the unmeasured angle of attack of the FAHV accurately and rapidly. Consequently, the estimation errors of the designed observer are convergent in a fixed time independent of their initial estimation errors. Furthermore, based on the estimated states, velocity and altitude tracking controllers are designed by using a finite-time adaptive IT2 fuzzy nonsmooth backstepping control technique, which avoids the problem of “explosion of complexity” in traditional backstepping methods. Subsequently, rigorous Lyapunov stability analysis is conducted to show the finite-time convergence of the closed-loop signals of the FAHV control system. Finally, the robustness and superiority of the proposed control scheme is validated by several simulations in representative scenarios.

  • fixed time control with uncertainty and measurement noise suppression for Hypersonic Vehicles via augmented sliding mode observers
    IEEE Transactions on Industrial Informatics, 2020
    Co-Authors: Jinlin Sun, Zhen Liu
    Abstract:

    Uncertainty and measurement noise are main obstacles that limit the tracking control performances of flexible air-breathing Hypersonic Vehicles (FAHVs). In this article, we propose a novel fixed-time convergent nonsmooth backstepping control scheme for FAHV via augmented sliding mode observers (ASMOs) to overcome these obstacles. The ASMOs are first designed for the FAHV dynamics by employing the measured states corrupted by noises as inputs. On one hand, the ASMOs can simultaneously estimate the uncertainties and filter out the measurement noises. On the other hand, the observation error of each ASMO can be convergent within a fixed time independent of its initial observation error. Then, based on the estimation results, the altitude and velocity tracking controllers are developed by using fixed-time nonsmooth backstepping technique. Afterwards, a Lyapunov-based stability analysis is given to illustrate the fixed-time convergence of the closed-loop signals of the FAHV control system. Finally, comparative simulations are conducted to illustrate the superiority of the proposed control scheme.

  • Conditional disturbance negation based active disturbance rejection control for Hypersonic Vehicles
    Control Engineering Practice, 2019
    Co-Authors: Jinlin Sun
    Abstract:

    Abstract This paper presents a conditional disturbance negation (CDN) based active disturbance rejection control (ADRC) scheme for the velocity and altitude tracking control of flexible air-breathing Hypersonic Vehicles (FAHVs) in the presence of various uncertainties and disturbances. A pioneering CDN module is proposed to selectively compensate the total disturbances according to the characteristics of the total disturbances and the FAHV dynamics, which is aimed at canceling some detrimental disturbances while profiting from other beneficial disturbances. Firstly, model-based extended state observers are applied to estimate the total disturbances in FAHVs in an efficient way. Based on the Lyapunov theory and the estimated disturbances, a novel disturbance characterization indicator (DCI) is then designed to show whether the total disturbance harms or benefits the tracking performance in engineering practice. Then, DCI is utilized to construct the CDN module. In consequence, the CDN based FAHV tracking control is implemented in an ADRC framework, yielding the CDN based ADRC scheme. The stability analysis is conducted to show the convergence of the closed-loop system. Finally, the effectiveness and superiority of the proposed control scheme are validated by some representative simulations in various flight conditions.