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Moving mass flight vehicles (MMFVs) with high-mass-ratio suffer from a more severe nonlinear attitude-servo coupling than the traditional configurations that are under particle moving mass hypothesis. Therefore, the coupled attitude-servo control problem is investigated in this paper, and an adaptive backstepping sliding mode controller with extended state observers and neural-networks (ABSMC-ENN) is proposed. Based on the formulated control model with strict-feedback form, a sliding mode control law (SMC) with exponential reaching rate and a nonsingular terminal sliding mode control law (NTSMC) are combined to perform the fast and robust tracking of the command angle-of-attack. Considering the disturbances and uncertainties existing in the coupled dynamics, two nonlinear extended state observers (ESOs) are utilized to estimate the total disturbances online for compensation. To further enhance the adaptiveness and dynamic response performances of the controller in various flight conditions, two radial basis function neural networks (RBFNNs) are exploited to optimize the switching gains of the controller in real-time with performance indexes being the functions of tracking errors. Closed-loop stability of the whole system is proved via Lyapunov methodology. Comparison simulation studies considering multiple disturbances, various flight conditions, and different controllers successfully demonstrate the superiority of the ABSMC-ENN in robustness and adaptiveness. [ABSTRACT FROM AUTHOR]

In this paper, the tracking control of the air-breathing hypersonic vehicle with model parameter uncertainties and actuator faults is studied. Firstly, a high-order linearization model is used to build an adaptive terminal sliding mode that eliminates chattering and provides increased robustness for unknown disturbances in the system. Second, a fault-tolerant control method mixing the radial basis function neural network with adaptive sliding mode control is suggested, with the addition of a hyperbolic tangent function to avoid controller input saturation. Finally, the stability of the controller is proved strictly by the Lyapunov theory, and the robustness and effectiveness of the controller are further verified by numerical simulations of the longitudinal model of the hypersonic vehicle. [ABSTRACT FROM AUTHOR]

In order to solve the attitude control problem of flexible hypersonic vehicles with consideration of aeroservoelastic effect, uncertainty and external disturbance, a novel moving-horizon-estimator-integrated adaptive hierarchical sliding mode control scheme is presented in this paper. First, the measurement model considering flexibility is established and the influence of aeroservoelastic effect on system stability is analyzed. Then moving horizon estimator is developed to reconstruct full state information from sensor measurements, while sliding mode disturbance observer and gain adaptation law is proposed to enhance the robustness and attenuate the chattering. Via combining moving horizon estimator, sliding mode disturbance observer, gain adaptation law and baseline hierarchical sliding mode controller, the moving-horizon-estimator-integrated adaptive hierarchical sliding mode control scheme that is able to achieve the control objective of both precise attitude control and active flexible vibration suppression is developed. Finally, Lyapunov theory is used to prove the stability of the proposed control scheme, and the numerical simulations are carried out, which further verify the effectiveness of the proposed control scheme against aeroservoelastic effect, uncertainty and external disturbance. [ABSTRACT FROM AUTHOR]

Abstract: Moving mass is one of the control actuators, whose configuration in the warhead is the basis of application in engineering for moving mass control technology. The servo forces, which drive the moving mass to move, affect the translational and rotational motion of the missile. It not only could increase the moving range of the center of system mass, but also reduce the requirement for the roll channel. Firstly, a single moving mass control mode, which consists of the rotation of rail around the longitudinal body-axis and the translation of the moving mass along the rail, is presented. Then, the 8-DOF dynamic model is established and the coupling characteristics between the attitude control and the servo-loop control are analyzed in this paper. Based on the above analysis, the attitude tracking control law is designed by using sliding mode theory. Finally, the problem about the terminal guidance of reentry vehicle is studied by numerical simulation: the state of moving mass is controlled by the servo force, and the missile attitude is controlled by adjusting the position of moving mass so that the excepted overload designed by using the proportion guidance could be tracked exactly. The simulation results verify the validity of the proposed method. [Copyright &y& Elsevier]

• This paper explores a three-dimensional tracking guidance strategy against high-maneuvering hypersonic vehicles. • The proposed guidance method utilizes a velocity control channel to increase tracking precision. • The wind field is accurately modeled to simulate the actual environment in the near-space to prevent impractical scenarios. • The backpropagation neural network extended state observer is proposed to estimate the uncertainty disturbance and design an adaptive control law to compensate for the tracking errors. • The proposed strategy combines fast nonsingular terminal sliding mode control and adaptive techniques to improve non-singularity, tracking accuracy, and estimation precision. This paper presents a three-dimensional disturbance observer-based adaptive tracking guidance scheme for the trajectory tracking problem of a missile intercepting a hypersonic vehicle with the wind field, autopilot lag dynamics, and input saturation. Unlike most of the existing missile trajectory tracking guidance systems without velocity controllability and external wind field model, the wind field model is added to the dynamic model, and the velocity control channel is introduced into the three-dimensional trajectory tracking guidance problem to prevent impractical scenarios and increase tracking precision. The proposed tracking guidance methodology incorporates the sliding mode and adaptive control techniques, in which the sliding mode motion is finite time stable independently of the tracking guidance system's initial conditions. Also, the super twisting switch control law is added to cope with the chattering problem. In this context, external uncertainty disturbances and unmeasured states are lumped into lump disturbance and estimated using the backpropagation neural network extended state observer. To this end, numerical simulations demonstrate the tracking to reach zero between 3 s and 5 s against various uncertainties in engineering practical, and position tracking errors are within 0.15 m, superior to the existing tracking guidance methods. [ABSTRACT FROM AUTHOR]

This work presents a novel real integrated guidance and control (IGC) scheme that solves the issues of underactuation, fixed-trim angle-of-attack and three-dimensional motion together for moving mass flight vehicles (MMFVs). Firstly, an underactuated IGC model containing the information of flight vehicle dynamics and three-dimensional relative motion is formulated, and the command error angle is designed to improve the capability of maneuvering penetration. Secondly, the modeled disturbances and uncertainties are regarded as the lumped disturbances, the values and derivatives of which are estimated by four second-order disturbance observers (DOs). Thirdly, different from the traditional backstepping-based partial IGC scheme, a novel sliding mode based real IGC law is designed, which generates the command moving mass offset input by only a single controller, thereby essentially eliminating the cross time-scale problem between the guidance and control loops. Moreover, this IGC law simultaneously achieves the command error angle tracking and the side-slip-angle stabilization with only a control input. Finally, the Lyapunov function is used to illustrate the asymptotic stability of the entire system, and numerical simulations with multiple disturbances, varied flying circumstances, and a comparison with other control strategies are carried out to show the effectiveness and superiority of the proposed IGC strategy. [ABSTRACT FROM AUTHOR]