Flight control for a flexible air-breathing hypersonic vehicle based on quasi-continuous high-order sliding mode

The focus of this paper is on control design and simulation for the longitudinal model of a flexible air-breathing hypersonic vehicle（FAHV）.The model of interest includes flexibility effects and intricate couplings between the engine dynamics and flight dynamics.To overcome the analytical intractability of this model,a nominal control-oriented model is constructed for the purpose of feedback control design in the first place.Secondly,the multi-input multi-output（MIMO） quasi-continuous high-order sliding mode（HOSM） controller is proposed to track step changes in velocity and altitude,which is based on full state feedback.The simulation results are presented to verify the effectiveness of the proposed control strategy.

Reference tracking control for flexible air-breathing hypersonic vehicle with actuator delay and uncertainty

This paper considers the problem of reference tracking control for the flexible air-breathing hypersonic flight vehicle with actuator delay and uncertainty.By constructing the Lyapunov functional including the lower and upper bounds of the time-varying delay,the non-fragile controller is designed such that the resulting closed-loop system is asymptotically stable and satisfies a prescribed performance cost index.The simulation results are given to show the effectiveness of the proposed control method,which is validated by excellent output reference altitude and velocity tracking performance.

Back-Stepping Control for Flexible Air-Breathing Hypersonic Vehicles Based on Uncertainty and Disturbance Estimator

A theoretical framework of nonlinear flight control for a flexible air-breathing hypersonic vehicle(FAHV)is proposed in this paper.In order to suppress the system uncertainty and external disturbance,an uncertainty and disturbance estimator(UDE)based back-stepping control strategy is designed for a dynamic state-feedback controller to provide stable velocity and altitude tracking.Firstly,the longitudinal dynamics of FAHV is simplified into a closure loop form with lumped uncertainty and disturbance.Then the UDE is applied to estimate the lumped uncertainty and disturbance for the purpose of control input compensation.While a nonlinear tracking differentiator is introduced to solve the problem of“explosion of term”in the back-stepping control.The stability of the UDE-based control strategy is proved by using Lyapunov stability theorem.Finally,simulation results are presented to demonstrate the capacity of the proposed control strategy.

HOSVD-based LPV modeling and mixed robust H_2/H_∞ control design for air-breathing hypersonic vehicle

This paper focuses on synthesizing a mixed robust H_2/H_∞ linear parameter varying（LPV） controller for the longitudinal motion of an air-breathing hypersonic vehicle via a high order singular value decomposition（HOSVD） approach.The design of hypersonic flight control systems is highly challenging due to the enormous complexity of the vehicle dynamics and the presence of significant uncertainties.Motivated by recent results on both LPV control and tensor-product（TP） model transformation approach,the velocity and altitude tracking control problems for the air-breathing hypersonic vehicle is reduced to that of a state feedback stabilizing controller design for a polytopic LPV system with guaranteed performances.The controller implementation is converted into a convex optimization problem with parameterdependent linear matrix inequalities（LMIs） constraints,which is intuitively tractable using LMI control toolbox.Finally,numerical simulation results demonstrate the effectiveness of the proposed approach.

New Weapon of Tomorrow’s Battlefield Driven by Hypersonic Velocity

Speed is the new stealth and earlier this week America’s top nuclear commander described a grim scenario for U.S.forces facing off against hypersonic weapons.“We do not have any defense that could deny the employment of such a weapon against us,”Air Force Gen.John Hyten,commander of U.S.Strategic Command,told the Senate Armed Services Committee on Tuesday March 20,2018.Russian and Chinese are aggressively developing new weapons that travel at Mach 5 or higher,which is at least five times faster than speed of sound(hypersonic).These weapons travel in excess of 3,600 miles per hour(1 mile per second)and currently,no military possesses a credible defense.Finding,tracking and intercepting something that fast is unprecedented.Given that Russia and China have invested heavily in advanced defensive technologies that now hold most of our traditional forms of power projection at risk,this is a significant advantage—it is one that would impose major costs upon a defending nation.Recently,according to the director of the Army’s Rapid Capabilities and Critical Technologies Office(ARCCTO),The Army will field a battery of truck-borne hypersonic missiles in 2023,with a contract award in August,the service’s new three-star Program Executive Officer said.The service will also field a battery of 50-kilowatt lasers on Stryker armored vehicles by 2021,he said.A program to put a 100-plus-kilowatt laser on a heavy truck,however,is under review and may be combined with Air Force and/or Navy efforts to reach comparable power levels,Lt.Gen.Neil Thurgood told reporters in his interview.In this white paper we are suggesting a new technology as a counter-measure against such an adversary measure and threat that is aggressively being pursued by these two nations,Russia and China both tactically and strategically.We also briefly discuss possible physics and science of aerodynamics involved with these vehicles traveling between range of 5 Mach and higher,where we discuss current status and future direction driven by phenomena of plasma aerodynamics thorough possibly,weakly ionized gases(WIG)program that was started by the former Soviet Republics under AJAX Vehicle and that was direct understanding of the role of plasmas in the performance of this vehicle.

Robust adaptive control of hypersonic vehicle considering inlet unstart

In this paper,a model reference adaptive control(MRAC)augmentation method of a linear controller is proposed for air-breathing hypersonic vehicle(AHV)during inlet unstart.With the development of hypersonic flight technology,hypersonic vehicles have been gradually moving to the stage of weaponization.During the maneuvers,changes of attitude,Mach number and the back pressure can cause the inlet unstart phenomenon of scramjet.Inlet unstart causes significant changes in the aerodynamics of AHV,which may lead to deterioration of the tracking performance or instability of the control system.Therefore,we firstly establish the model of hypersonic vehicle considering inlet unstart,in which the changes of aerodynamics caused by inlet unstart is described as nonlinear uncertainty.Then,an MRAC augmentation method of a linear controller is proposed and the radial basis function(RBF)neural network is used to schedule the adaptive parameters of MRAC.Furthermore,the Lyapunov function is constructed to prove the stability of the proposed method.Finally,numerical simulations show that compared with the linear control method,the proposed method can stabilize the attitude of the hypersonic vehicle more quickly after the inlet unstart,which provides favorable conditions for inlet restart,thus verifying the effectiveness of the augmentation method proposed in the paper.

Prescribed fast tracking control for flexible air-breathing hypersonic vehicles:An event-triggered case

In this paper,a prescribed fast tracking control scheme is proposed for Flexible Airbreathing Hypersonic Vehicles(FAHV)subject to lumped disturbances and limited resources.To maintain tracking errors of velocity and altitude converge to a predefined region with a prescribed time and release the transient intense fluctuations encountered in classical Prescribed Performance Control(PPC)using a fast decaying rate,a tracking differentiator-based PPC is presented,where the reaching time and the maximum time differentiation of preselected envelopes can be regulated as a prior via fixing an acceleration factor,so that a guaranteed fast convergence speed can be realized with reduced oscillations.Besides,to avoid the excessive occupation of limited resources(energy and communication)and guarantee a remarkable tracking accuracy,switching event-triggered mechanisms are constructed for FAHV control realization,which provide a promising way to pursue a desired level of tracking performance with a low energy consumption.Subsequently,Uncertainty and Disturbance Estimators(UDE)and Sigmoid function-based Tracking Differentiators(STD)are employed to provide disturbance estimation and reference derivation with a low computational complexity.Finally,robust control laws are designed to compensate for the sampling error induced by event-triggered conditions,meanwhile Zeno phenomena can be effectively eliminated.The simulation results and comparisons validate the effectiveness of the proposed scheme.

Flight control for air-breathing hypersonic vehicles using linear quadratic regulator design based on stochastic robustness analysis

The flight dynamics model of air-breathing hypersonic vehicles （AHVs） is highly nonlinear and multivariable cou- pling, and includes inertial uncertainties and external disturbances that require strong, robust, and high-accuracy controllers. In this paper, we propose a linear-quadratic regulator （LQR） design method based on stochastic robustness analysis for the longitudinal dynamics of AHVs. First, input/output feedback linearization is used to design LQRs. Second, subject to various system parameter uncertainties, system robustness is characterized by the probability of stability and desired performance. Then, the mapping rela- tionship between system robustness and LQR parameters is established. Particularly, to maximize system robustness, a novel hybrid particle swarm optimization algorithm is proposed to search for the optimal LQR parameters. During the search iteration, a Chernoff bound algorithm is applied to determine the finite sample size of Monte Carlo evaluation with the given prohabilily levels. Finally, simulation results show that the optimization algorithm can effectively find the optimal solution to the LQR parameters.

Lines cluster approaching mode control for air-breathing hypersonic vehicle under disturbances and uncertainties

This paper investigates the velocity and altitude tracking control problem for airbreathing hypersonic vehicle(AHV)in the presence of external disturbances and parameter uncertainties.A composite controller containing improved lines cluster approaching mode control(LCAMC)and nonlinear disturbance observer(NDO)is developed to guarantee the tracking errors converge to zero and enhance the robustness of control system.Meanwhile,considering the multiple uncertain parameters,a genetic algorithm(GA)based Pareto uncertainty estimation is employed to predict the parameter uncertainties of the AHV dynamics.Besides,the mathematical proofs of proposed method are analyzed by utilizing Lyapunov theory.Simulation results demonstrate the effective tracking performance,excellent disturbance estimation and uncertainty estimation ability of the composite method.

H-infinity control for air-breathing hypersonic vehicle based on online simultaneous policy update algorithm

Purpose–The air-breathing hypersonic vehicle(AHV)includes intricate inherent coupling between the propulsion system and the airframe dynamics,which results in an intractable nonlinear system for the controller design.The purpose of this paper is to propose an H1 control method for AHV based on the online simultaneous policy update algorithm(SPUA).Design/methodology/approach–Initially,the H1 state feedback control problem of the AHV is converted to the problem of solving the Hamilton-Jacobi-Isaacs(HJI)equation,which is notoriously difficult to solve both numerically and analytically.To overcome this difficulty,the online SPUA is introduced to solve the HJI equation without requiring the accurate knowledge of the internal system dynamics.Subsequently,the online SPUA is implemented on the basis of an actor-critic structure,in which neural network(NN)is employed for approximating the cost function and a least-square method is used to calculate the NN weight parameters.Findings–Simulation study on the AHV demonstrates the effectiveness of the proposed H1 control method.Originality/value–The paper presents an interesting method for the H1 state feedback control design problem of the AHV based on online SPUA.

临近空间高超音速武器防御综述

临近空间高超音速武器防御是当前防空领域的热点。文中系统地归纳了当前临近空间超高音速武器的发展现状和作战特点,在详细分析临空类武器对防御系统威胁和挑战的基础上,提出了对防空系统的顶层能力需求,可为新一代防空体系需求分析研究提供一定的参考。

密集阵武器拦截高超音速导弹有效性分析

通过研究高超音速导弹(HM)对舰载近程武器系统(CIWS)的突防能力,探讨利用CIWS拦截HM的可行性.根据选取的CIWS和HM原型,建立了HM的三维比例导引攻击模型、CIWS拦截模型以及弹丸散布模型,研究了HM爆炸破片的后续杀伤能力,进一步分析了HM的攻击速度、方向以及外形尺寸等与HM突防能力之间的关系.借助Monte Carlo法仿真分析了CIWS对不同HM原型的拦截效果,讨论了改进措施的可行性.结果表明,现有条件下利用CIWS无法有效拦截HM,需要探讨新的技术途径.

基于自适应动态规划的反高超武器微分对策制导律

随着各国高超声速技术的武器化进程加快,对反高超声速武器拦截技术的研究也不断深入,高超声速武器高速度、大范围主动博弈突防的拦截制导问题成为拦截制导律设计领域的研究热点。针对具有主动博弈突防能力的高超声速目标拦截场景进行微分对策问题建模,并采用基于双启发式的自适应动态规划算法,对连续非线性系统的微分对策纳什均衡解进行求取;通过Matlab数字仿真对设计的拦截制导方法进行验证。结果表明:相较于最优滑模制导律,基于自适应动态规划的微分对策制导律对目标的逃逸机动具有更强的适应性,能够获得更高的拦截精度。

密集阵对高超音速导弹的多点瞄准拦阻模型

单座密集阵近程武器系统（CIWS）在传统集火跟踪射击方式下难以拦截高超音速导弹（HM）,针对此问题,提出了一种连续跟踪、多点瞄准、集火射击的拦截模型,阐述了多点瞄准连续射击体制的原理,给出了易于工程实现的多瞄准点构造方法.在HM与CIWS的动态对抗中,建立了HM在不同飞行速度及入射角下的受弹圆模型,对比分析了2种射击体制下CIWS对HM的平均命中弹数和拦截概率.实验结果表明,采用多点瞄准连续射击方法,CIWS对HM的平均命中弹数比传统方法略低,但对HM的拦截概率要比传统方法提高28％～32％,研究结果为HM的末端拦截策略提供了一种新的技术参考.

高超声速武器系统作战能力

首先,讨论了高超声速武器发展情况;然后,介绍了高超声速武器,包括高超声速巡航导弹、高超声速下滑弹头和高超声速侦察机的战术技术特性;接着,给出了高超声速武器系统作战能力的计算方法,并列举了高超声速进攻和高超声速防御2个武器系统的作战能力计算公式;最后,分析了高超声速武器系统作战能力计算的重要性。

发展中的高超声速武器及其战略意义

速度是武器系统的一项重要指标,高超声速武器技术是武器技术发展中的一个重要里程碑,是自隐身技术问世以来在军事技术方面最重要的进展。高超声速武器将成为未来空天力量对抗中至关重要的武器,对于未来战争的作战模式、作战过程及战争结局将产生重大影响。目前,军事大国和一些发达国家都已制定了一系列高超声速武器发展计划,研究与试验工作也取得了重大进展。

即时全球打击(PGS)武器早期预警对光电探测器的需求分析

介绍了在近地空间环境的理想条件下,即时全球打击(prompt global strike,PGS)武器地球曲率限的最大可探测距离的计算方法。根据黑体辐射理论,估算了PGS在短波红外和日盲紫外波段的辐射量值。当PGS飞行速度高于5马赫数时,其辐射峰值波长位于短波红外波段,最适合使用短波红外探测器。虽然与短波红外能量相比,PGS的紫外辐射能量要小得非常多,但其紫外辐射光子个数仍然是一个巨量的值。具有单光子计数能力的短波红外和日盲紫外雪崩光电二极管或有实现PGS早期预警及最大可探测距离的潜力。

天基跟踪层星座性能建模与仿真

随着高超声速武器技术的快速发展和实战化部署,美国有针对性地提出了建设国防太空架构跟踪层计划的设想。首先,介绍了跟踪层卫星主要设计性能参数;其次,建立了跟踪层星座覆盖性能分析模型、探测能力分析模型和跟踪性能分析模型;最后,通过仿真计算对跟踪层系统性能进行了分析,并推断了系统全星座最小卫星数量、探测灵敏度和全球目标最优跟踪精度等核心能力。分析结果对相关系统信息处理算法研究、载荷与星座方案设计具有重要参考价值。

国外高超声速武器发展动态

高超声速武器兼具极高的战术实用性与战略威慑性,这类先进武器正受到世界范围内的关注,高超声速武器技术开发呈现出竞争扩散态势。主要梳理了美俄高超声速武器发展的最新动态,从武器的列装情况和预研项目的研发进度2个方面展示了国外关于高超声速武器的最新成果。

美军针对高超声速武器的反导预警能力发展态势分析

高超声速武器具有飞行速度快、精确毁伤和高效突防等特点,具有重要的战略威慑和实战应用价值,它能够大幅改变未来战争的态势,已成为大国打破战略平衡、打赢未来战争的新型“杀手锏”。随着高超声速武器逐步走向战场,世界各主要国家的反导防御体系将向更高预警维度、更快反应速度和更大打击力度的天地一体联合防御方向发展。本文分析了高超声速武器作战优势及其对未来战争的影响和威胁,阐述了美军现有反导预警能力的基本架构与能力缺陷,对其未来反高超声速武器的预警能力建设及发展态势进行了研判与预测。美军“优先发展天基反导作战体系,发挥低轨卫星主体作用”的反高超声速武器发展思路对于军队反导反高超声速武器能力建设具有一定的启示和借鉴作用。