基于移动最小二乘法的气动力数据建模方法

针对一体化飞行器高度耦合的非线性气动问题,提出了一种基于移动最小二乘法的气动力数据建模方法;首先,对影响模型精度的因素进行了分析;接着,在构建移动最小二乘模型时采用遗传算法获取最佳支撑域半径以及最佳影响因子β,提高近似精度从而达到减少样本点的目的;得到泛化能力较强的气动力模型,并与偏最小二乘方法的建模结果进行对比;实验结果表明:移动最小二乘法的建模效果优于偏最小二乘方法,预测误差较小,证明了将该方法应用于气动数据建模是可行的。     

飞翼飞机嵌入式大气数据系统算法研究

为适应新型作战飞行器平台高隐身、高超声速、高机动性等方面的需求,嵌入式大气测量技术不断发展。分析对比类球头集中式和飞翼飞机分布式两大类嵌入式大气数据传感（FADS）系统的研究情况及差异性。针对高隐身的飞翼布局飞机,以类X-47B飞机气动外形为研究对象,参考其测压点选位布局,开展了FADS算法模型的研究,提出一种适合工程应用的飞翼布局飞机FADS算法模型。算法采用最小二乘法拟合流场样本数据,通过迭代计算解耦各大气参数。仿真验证表明：该算法具有较高的解算精度,且迭代计算稳定收敛。     

基于Backstepping的高超声速飞行器模糊自适应控制

提出了高超声速飞行器的模糊自适应控制方法.根据飞行器纵向模型的特点,分别设计了基于动态逆的速度控制器和基于Backstepping的高度控制器,模糊自适应系统用来在线辨识飞行器模型由于气动参数的变化而引起的不确定性,采用Lyapunov理论设计的自适应律保证了系统的稳定性与指令跟踪的精确性.仿真使用了高超声速飞行器的纵向模型对算法进行了验证,得到了较满意的控制效果.     

基于改进卡尔曼滤波的四维飞行航迹预测模型

为解决空气动力学模型在四维飞行航迹预测中存在的参数过多、预测精度偏低等问题,提出了一种对预测模型中的系统噪声进行实时估计的改进卡尔曼滤波（IKF)算法。首先,对雷达数据进行处理,根据航空器飞行中航向、航速进行速度转换;然后,采用传统卡尔曼滤波(KF)算法和IKF算法分别建立航迹预测模型;最后通过同一实例计算,比较两种算法在X、Y、Z方向上的预测偏差,取偏差小者为优。实验结果表明：IKF算法在X、Y方向上的预测偏差比KF算法分别降低了17.65%和98.03%,而Z方向上采用KF算法有较小的预测偏差。此外,针对IKF算法进行不同时间间隔的预测分析,在进场飞行程序的保护区宽度(9.46km)范围内,预测间隔可以增大至20s。     

Terminal open-loop control for a hypervelocity unmanned flying vehicle in the atmosphere. Part 1

An algorithm for the terminal open-loop control of a hypervelocity flying vehicle with a high lift-drag (L/D) ratio is proposed; this algorithm ensures the implementation of spatial programmed hitting trajectories steering the vehicle to the given spatial domain with required high accuracy and required conditions of approaching this domain. The algorithm is based on the a priori construction of a rational hitting trajectory and the corresponding control vector; the control vector components are the attack and bank angles. At the beginning of the terminal phase, only constraints on the individual components of the vector of initial conditions are imposed: the ranges of altitudes, velocities, and flight path angle. In addition, the requirement for the minimum admissible resolution of the onboard radar that provides informational support at the terminal phase is taken into account in the trajectory construction. Examples of programmed hitting trajectories are given that confirm the fact that the proposed algorithm for the generation of such trajectories and the corresponding attainability sets is computationally efficient.     

Terminal synthesis of orbital orientation for a spacecraft

This paper presents an algorithm for the terminal synthesis of the orbital orientation for a spacecraft. The algorithm is based on solving the following problems: the analytical determination of the program values for the angular velocity vector components in an orbital coordinate system and the stabilization of the program values for the turn rate vector components and the desired terminal angular position of a spacecraft. The program values of the angular velocity vector components are determined analytically using the method previously proposed by the authors for solving a boundary value problem based on the parameter identification of a discrete model with the use of modal control. The simulation results demonstrating the effectiveness of the proposed algorithm, as well as the high accuracy level of the steady-state control, are presented.     

Neural-fuzzy scheduling of H robust controllers for a high performance fighter aircraft under a Herbst-like manoeuvre

This paper presents a flight control system design method witha neural-fuzzy gain-scheduling algorithm with learning capability for a high performance fighter aircraft undergoing a high angle of attack velocity vector roll manoeuvre. This manoeuvre is similar to the Herbst manoeuvre, hence also called a Herbst-like manoeuvre. Two linear H robust controllers are designed by using the mu -synthesis method at two trim conditions that cover the whole dynamic range of this manoeuvre. Then a scheduling technique is proposed, using the neural-fuzzy concept, together witha dynamic back propagation algorithm for its training. Simulation results, using a recently developed non-linear six-degree-of-freedom aircraft simulation package, demonstrate that the neural-fuzzy scheduler can be trained by using the dynamic back propagation algorithm to achieve better closed-loop tracking performance, and the proposed neural-fuzzy scheduled flight control system gives satisfactory performance inexecuting this Herbst-like manoeuvre.     

基于气动参数调节的无人机抗扰动控制算法

无人机飞行受到气动阻尼扰动,从而导致控制稳定性不好。当前采用翼型截面气动参数调节的方法进行无人机抗扰控制,以扭角以及振动方向等参数为约束指标,参数调节的模糊度较大,对气动姿态参数调节的稳定性不好。文中提出基于气动参数调节的无人机抗扰动控制算法。该算法根据无人机的飞行工况构建各阶模态对应的气弹耦合方程,在速度坐标系、体坐标系、弹道坐标系三维坐标系下构建无人机的飞行动力学和运动学模型;采用卡尔曼滤波方法实现对无人机飞行参数的融合调节和小扰动抑制处理,并采用末端位置参考模型进行无人机飞行轨迹的空间规划设计;在卡尔曼滤波预估模型中实现对动力学模型的线性化处理,采用气弹模态参数识别方法进行无人机的飞行扰动调节;将姿态控制作为内环,获得位置环状态反馈调节参数;以无人机的升力系数和扭力系数作为气动惯性参数进行飞行姿态的稳定性调节,从而实现无人机抗扰动控制律的优化设计。采集飞机的俯仰角、横滚角和航向角作为原始数据在Matlab中进行仿真分析,仿真结果表明,采用所提方法进行无人机抗扰动控制的稳定性较好,对气动参数进行在线估计的准确性较高,航向角误差降低12.4%,抗扰动能力提升8dB,收敛时间比传统方法缩短0.14 s,无人机飞行的抗扰动性和飞行稳定性得到提高。所提方法在无人机飞行控制中具有很好的应用价值。     

气动模型及导航信息辅助的大气参数估计方法

针对无初始风速信息情况下的虚拟大气数据计算问题,提出一种气动模型及导航信息辅助的大气参数粗精两级估计方法.利用飞行器气动模型下的动力学方程,建立与风速直接相关的导航传感器测量模型;采用非线性最小二乘优化方法对风速进行一级估计,并作为滤波初始值;利用扩展卡尔曼滤波,对风速进行二级估计,进而实现大气参数的实时精确估计.实验结果表明,所提方法具有较高的收敛速度和估计精度,可提高大气数据系统的测量范围和可靠性,适用于全飞行包线下攻角、侧滑角、真空速的测量.     

Embedded Parallelization Approach for Optimization in Aerodynamic Design

A new efficient parallelization strategy for optimization of aerodynamic shapes is proposed. The optimization method employs a full Navier-Stokes solver for accurate estimation of the objective function. As such it requires huge computational resources which makes efficient parallelization crucial for successful promotion of the method to an engineering environment. The algorithm is based on a multilevel embedded parallelization approach, which includes (1) parallelization of the multiblock full Navier-Stokes solver with parallel CFD evaluation of objective function, (2) parallelization of optimization process with parallel optimal search on multiple search domains and, finally, (3) parallel grid generation. Applications (implemented on a 144-processors distributed memory cluster) include various transonic profile optimizations in the presence of nonlinear constraints. The results demonstrate that the approach combines high accuracy of optimization with high parallel efficiency. The proposed multilevel parallelization which efficiently makes use of computational power supplied by multiprocessor systems, leads to a significant computational time-saving and allows application of the method to practical aerodynamic design in the aircraft industry.     

Flight envelope protection of aircraft using adaptive neural network and online linearisation

Flight envelope protection algorithm is proposed to improve the safety of an aircraft. Flight envelope protection systems find the control inputs to prevent an aircraft from exceeding structure/aerodynamic limits and maximum control surface deflections. The future values of state variables are predicted using the current states and control inputs based on linearised aircraft model. To apply the envelope protection algorithm for the wide envelope of the aircraft, online linearisation is adopted. Finally, the flight envelope protection system is designed using adaptive neural network and least-squares method. Numerical simulations are conducted to verify the performance of the proposed scheme.     

火箭返回着陆问题高精度快速轨迹优化算法

针对垂直起降可重复使用运载火箭子级返回着陆问题,提出一种高精度快速轨迹优化算法.算法将凸化技术与伪谱离散方法有机结合,将非凸、非线性优化问题转化为凸优化问题,进而充分利用凸优化求解快速性、收敛确定性以及伪谱法离散精度高的理论基础.在优化精度方面,建立了高保真优化模型,分析了发动机开机/终端时刻值设计对轨迹最优性的影响;采用flip-Radau谱法对连续最优控制问题进行离散,并利用伪谱法的独特离散时域映射,将开机和终端时刻设计为特殊控制变量,提高了优化结果的精度和最优性.在快速性方面,为利用凸优化方法求解非凸问题,基于一种新的信赖域更新策略,提出了改进序列凸化算法,减少了算法迭代次数,提高了算法收敛性能.数值实验验证了算法的有效性.高精度的优化结果和较高的计算速度,使得算法具有发展为在线最优制导方法的潜力.     

基于自适应二阶终端滑模的飞行器再入姿态控制

针对飞行器再入过程中存在着模型不确定性因素以及气动环境复杂等鲁棒控制问题,提出一种基于自适应二阶非奇异终端滑模的控制方案.设计的控制器保证姿态跟踪误差在有限的时间内收敛于零,不需要内外扰的先验知识,通过在线自适应辨识扰动上界以消除其影响.最后以气动参数摄动50%作为扰动条件进行了飞行器再入姿态控制仿真,结果表明了该方案的快速性和鲁棒性.     

基于AFSMC算法的飞机飞行姿态自适应滑模控制系统

传统飞机飞行姿态滑膜控制系统,存在飞机飞行姿态自适应系数稳定性差的问题,在控制过程中会受到多重因素影响,导致飞行姿态可控误差系数增大,需要辅助控制系统修正才能完成飞行姿态的控制操作;针对上述问题,提出基于AFSMC算法的飞机飞行姿态自适应滑模控制系统;系统硬件基于PID自适应滑模控制器,对飞机飞行姿态控制器进行结构设计;软件部分通过引入自适应滑模控制策略,对PID控制器姿态控制变量进行适配;引入AFSMC算法计算姿态控制器当前时间点下的运动控制方程,得到飞行姿态自适应滑模控制的最优量,完成基于AFSMC算法的飞机飞行姿态自适应滑模控制系统设计;实验结果表明,所设计系统能够在不同飞行工况下,对飞机飞行姿态作出准确控制,系统的整体控制精度范围为90%~97.4%,飞机飞行控制稳定性较好,有效提升了系统对飞机飞行姿态的控制准确度。     

Direct adaptive neural flight control system for an unstable unmanned aircraft

A direct adaptive controller design using neural network is proposed for an unstable unmanned research aircraft similar in configuration to combat aircraft. The control law to track the pitch rate command is developed based on system theory. Neural network with linear filters and back propagation through time learning algorithm is used to approximate the control law. The bounded signal requirement to develop the neural controller is circumvented using an off-line finite time training scheme, which provides the necessary stability and tracking performances. On-line learning scheme is implemented to compensate for uncertainties due to variation in aerodynamic coefficients, control surface failures and also variations in center of gravity position. The performance of the proposed control scheme is validated at different flight conditions. The disturbance rejection capability of the neural controller is analyzed in the presence of the realistic gust and sensor noises. Hardware-in-loop simulation is also carried out to study the behavior of control surface deflections in real-time.     

面向分级设计优化的飞行器参数化建模方法

针对飞行器气动隐身外形综合设计优化问题,提出合适的面向分级设计优化流程,建立适应该流程的渐进分层参数化建模方法;用基于敏度分析的参数影响程度分析方法筛选复杂设计变量;采用多学科设计优化（Multidisplinary Design Optimization,MDO）理论和差分进化算法进行飞行器气动隐身外形的综合设计优化.将该方法用于某飞行器外形设计优化,结果表明：该方法合理可行,可为飞行器外形多学科设计优化提供一定参考.     

Aerodynamic shape optimization of supersonic aircraft configurations via an adjoint formulation on distributed memory parallel computers

This work describes the application of a control theory-based aerodynamic shape optimization method to the problem of supersonic aircraft design. A high fidelity computational fluid dynamics (CFD) algorithm modelling the Euler equations is used to calculate the aerodynamic properties of complex three-dimensional aircraft configurations. The design process is greatly accelerated through the use of both control theory and parallel computing. Control theory is employed to derive the adjoint differential equations whose solution allows for the evaluation of design gradient information at a fraction of the computational cost required by previous design methods. The resulting problem is then implemented in parallel using a domain decomposition approach, an optimized communication schedule, and the Message Passing Interface (MPI) Standard for portability and efficiency. In our earlier studies, the serial implementation of this design method, was shown to be effective for the optimization of airfoils, wings, wing–bodies, and complex aircraft configurations using both the potential equation and the Euler equations. In this work, our concern will be to extend the methodologies such that the combined capabilities of these new technologies can be used routinely and efficiently in an industrial design environment. The aerodynamic optimization of a supersonic transport configuration is presented as a demonstration test case of the capability. A particular difficulty of this test case is posed by the close coupling of the propulsion/airframe integration.     

基于工程约束与权重优化的民机部段柔性调姿算法实现

民用飞机具有产品复杂、气动外形要求严格、产品构型众多、零部件数量巨大等特点,飞机制造过程中装配技术要求和工作量占比远高于其他一般的机械产品加工行业.调姿对接装配是装配工作的重要内容,高精度、低应力的对接装配是飞机成功制造和安全飞行的保证.基于奇异值解算与优化算法,根据民机装配工艺要求,在Python环境下开发并实现无权...     

基于图像处理和模糊控制的飞机泊位模拟系统研究

为了解决民航类专业学生及航司员工的教学及培训中无法明确了解飞机泊位系统原理和关键技术的问题,基于图像处理算法和模糊控制对飞机泊位模拟系统进行了研究,其中基于颜色识别的算法进行泊位线的提取,针对不同的颜色识别结果基于模糊控制决策表做出相应的飞机模型运动控制,在室外和室内环境下进行了实验,实验证明算法具备较高的可靠性,系统能够较好的完成飞机泊位引导过程的模拟。     

振动模糊星图仿真技术研究

分析了飞行器振动对星敏感器成像的影响,推导并建立该影响下星图模糊的数学模型。该模型首次通过角振动功率谱密度数据定量地模拟星点的随机振动轨迹,并在此基础上做出振动对星敏感器成像的影响分析。仿真结果表明,该方法可以较真实地模拟星图振动模糊效果。星点质心提取精度与角振动功率谱幅值在对数域上线性相关。