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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]

Aiming at the trajectory prediction problem in hypersonic glide vehicle defense, novel trajectory prediction algorithms based on maneuver mode on-line identification and intent inference are proposed. For solving the maneuver mode identification and modeling problems, the auto-regressive method is introduced to reveal the hidden internal law in the historical tracking data and present the parametric model of the maneuver mode, thereby realizing the accurate trajectory prediction. To deal with the maneuver mode mutation problem, a novel intent inference based long-term trajectory prediction algorithm is proposed: firstly, the cost function of maneuver intent is constructed reasonably. Then, to solve the vehicle's intent recursive calculation problem, the recurrence formula of the vehicle's intent is derived based on Bayesian estimation theory, and the vehicle's reachable region rapid resolution and discretization methods are proposed. Finally, the vehicle's state recursive formula is derived with Bayesian estimation theory, and the trajectory prediction problem is transformed into the probability prediction problem of the vehicle appearing in a specific region. To avoid the large calculation problem in long-term trajectory prediction, the random sampling shooting method is adopted. The proposed trajectory prediction algorithms are combined to are combined to realize complementary advantages and provide as much valuable prediction information as possible for the defender. The simulation results show that the proposed trajectory prediction algorithms share high prediction accuracy and applicability. [ABSTRACT FROM AUTHOR]

Considering the nonlinearity, uncertainty, and rigid/elastic coupling, a state/parameter joint estimation method is essential for control system design or fault diagnosis of flexible hypersonic vehicles. With the goal of improving state/parameter estimation accuracy, this paper proposes a sensor placement strategy and a moving horizon estimation algorithm with a QR-decomposition-based arrival cost update strategy (MHE-QR). To enhance observability, a novel double sensor placement strategy, in which the sensor positions are obtained via solving a constrained nonlinear optimization problem, is developed. The MHE-QR algorithm transforms the arrival cost update problem into a least square problem and solves it utilizing QR decomposition. With this QR-decomposition-based arrival update strategy, the state/parameter estimation problem is solved as a nonlinear programming problem in the framework of moving horizon estimation. Finally, the performance of sensor placement strategy and MHE-QR is evaluated by Monte Carlo simulations in 10 different scenarios. Simulation results demonstrate that the sensor placement strategy and MHE-QR algorithm can effectively improve the estimation accuracy, convergence speed and computation rate. Additionally, the CPU time of MHE-QR validates its real-time applicability. [ABSTRACT FROM AUTHOR]

The maneuver modes in the glide phase are explored from the perspective of hypersonic vehicle defense in this study, and a novel maneuver mode description approach is proposed. The longitudinal and lateral maneuver modes' mechanisms and evolution laws are explored. And, the focus of this research is on the evolution laws of complex lateral maneuver modes in real scenarios. To solve the maneuver mode description problems, a novel maneuver mode parametric analyzing and modeling method is proposed based on the Vector Auto-regressive model. Firstly, the Granger causality test is adopted to verify whether there are causal correlations between the maneuver characteristic parameter series, which have a high level of regularity and are taken as modeling variables. Then, the Vector Auto-regressive method is employed to model the coupling relationship between the maneuver characteristic parameters, as well as to provide a precise description method with simple structure and uniform form for various maneuver modes. Moreover, the model coefficients estimation and model order selection methods are presented. This study helps to deepen the understanding of the target's maneuver modes in hypersonic vehicle defense. Simulation results demonstrate that the proposed modeling method can greatly improve modeling accuracy. [ABSTRACT FROM AUTHOR]

This paper concerns the attitude dynamics and control synthesis of fixed-trim moving mass reentry vehicle (MMRV) suffering from stochastic uncertainties. In order to enhance the roll maneuverability, a new high-mass-ratio configuration is proposed and analyzed. The attitude dynamic analysis presents that the steady-state angle of attack and the interference on yaw channel increase with the mass ratio of moving mass to the whole aircraft as well as the distance between the moving mass mass centre and the vehicle body mass centre. Also, the roll control authority and roll maneuverability are proved to be enhanced when the mass ratio is higher. Considering the practical multi-source disturbances caused by aerodynamic parameter perturbation and stochastic disturbances, the parameter adaptive law and extended state observers (ESOs) are introduced into the control scheme and developed through backstepping design procedure. Meanwhile, an auxiliary system is introduced to compensate for the control saturation caused by the limitation on the moving mass deflection angle. With the aid of Lyapunov function and Ito differential rule, the adaptive backstepping ADRC controller is designed with a guarantee of uniformly ultimate boundness (UUB) of the closed-loop tracking error in mean square. Simulation results are presented to demonstrate the validity and superiority of the proposed configuration and controller. [ABSTRACT FROM AUTHOR]