Dynamics modeling and control of large transport aircraft in heavy cargo extraction

In this paper,a novel version of six-degree-of-freedom nonlinear model for transport aircraft motion in cargo extraction is developed and validated by the theoretical mechanics and flight mechanics.In this model constraint force and moment reflecting the flight dynamic effects of inner moving cargo are formulated.A methodology for a control law design in this phase is presented,which linearizes the aircraft dynamics making use of piecewise linearization and utilizes robust control technique for interval system to achieve specified handling qualities with robustness to uncertainties.The simulations demonstrate adequate effectiveness and excellent robustness of the proposed controller.     

基于模型的空投任务飞行品质试飞设计及评估

针对飞机执行空投任务的飞行品质试飞安全控制及缺少设计及评估方法问题,建立空投过程数学模型,预测空投过程飞机响应、指导飞行试验实施,在空投试飞前,为评估飞机空投构型飞行品质、确保空投试飞的安全性,分析空投货物时飞机响应特点,确定载机平台飞行品质试飞内容;以飞机姿态控制为目标,确定重力空投、牵引空投过程飞机飞行状态、给出飞行员操纵建议,设计了空投过程评价要素表,形成基于模型的空投任务飞行品质试飞设计及评估技术,保障试飞安全、指导试飞设计。     

An algorithm for trajectory prediction of flight plan based on relative motion between positions

Traditional methods for plan path prediction have low accuracy and stability. In this paper, we propose a novel approach for plan path prediction based on relative motion between positions (RMBP) by mining historical flight trajectories. A probability statistical model is introduced to model the stochastic factors during the whole flight process. The model object is the sequence of velocity vectors in the three-dimensional Earth space. First, we model the moving trend of aircraft including the speed (constant, acceleration, or deceleration), yaw (left, right, or straight), and pitch (climb, descent, or cruise) using a hidden Markov model (HMM) under the restrictions of aircraft performance parameters. Then, several Gaussian mixture models (GMMs) are used to describe the conditional distribution of each moving trend. Once the models are built, machine learning algorithms are applied to obtain the optimal parameters of the model from the historical training data. After completing the learning process, the velocity vector sequence of the flight is predicted by the proposed model under the Bayesian framework, so that we can use kinematic equations, depending on the moving patterns, to calculate the flight position at every radar acquisition cycle. To obtain higher prediction accuracy, a uniform interpolation method is used to correct the predicted position each second. Finally, a plan trajectory is concatenated by the predicted discrete points. Results of simulations with collected data demonstrate that this approach not only fulfils the goals of traditional methods, such as the prediction of fly-over time and altitude of waypoints along the planned route, but also can be used to plan a complete path for an aircraft with high accuracy. Experiments are conducted to demonstrate the superiority of this approach to some existing methods.     

运动模型式飞行器气动力参数测试系统研究

为了对飞行器进行气动布局、飞行性能评估,提出了一种运动模型式气动力参数测量方法,并研制了一套运动模型式测试系统,通过运动模型来模拟飞行器在空气中的运动,其构造主要包含载具、测试支架、六分量天平、风速测量模块、数据采集模块、控制模块、便携计算机等部分;该类测试系统在某些特定工况下能准确模拟飞行器的飞行状态,对流场参数和模型所受载荷进行实时测量,预测各运动状态下飞行器的气动特性;通过数值模拟分析和风洞实验对车载试验数据进行了对比验证,结果表明,该测试系统能够准确获得模型的气动力特性数据;该系统具有一定的拓展性和通用性,可使用火箭橇等其他载具开展高速运动模型式气动力参数测量试验。     

基于QAR数据的民航客机设计理念分析

中国国内运行着大量国外先进民用飞机。这些飞机全部装有飞行数据快速存取记录器,以采集飞行数据开展飞行品质监控工作;民机日常飞行数据除了能够在航空公司运行中发挥作用,还能够通过技术手段分析得出先进型号的设计经验与运行特点,相关技术成果对国产民机制造业的发展也具有一定的借鉴意义;在分析国内外相关研究基础上,以两款国外民机巡航段飞行数据的分析为例,解析了两型飞机的高度保持控制律设计逻辑,实际案例分析表明,基于QAR数据的分析能够有效地反应在自动飞行阶段高度保持控制律中体现的设计逻辑,从而有助于对国产民机的设计和优化。     

Robust identification method for nonlinear model structures and its application to high-performance aircraft

A common assumption is that the model structure is known for modelling high performance aircraft. In practice, this is not the case. Actually, structure identification plays the most important role in the processing of nonlinear system modelling. The integration of mode structure identification and parameter estimation is an efficient method to construct the model for high performance aircraft, which is nonlinear and also contains uncertainties. This article presents an efficient method for identifying nonlinear model structure and estimating parameters for high-performance aircraft model, which contains uncertainties. The parameters associated with nonlinear terms are considered one after the other if they should be included in the nonlinear model until a stopping criterion is met, which is based on Akaike's information criterion. A numerically efficient U-D factorisation is presented to avoid complex computation of high-order matrices. The proposed method is applied to flight test data of a high-performance aircraft. The results demonstrate that the proposed method could obtain the good aircraft model with a reasonably good fidelity based on the comparison with flight test data.     

A moving window parameter adaptive control system for the F8-DFBW aircraft

This paper describes the moving window parameter adaptive control system developed for the NASA F8-DFBW aircraft. The control system employs a parameter identification process that, iteratively, adjusts parameters of a model of the aircraft motions in a batch-processing manner so that responses generated from the model fit the outputs of sensors stored in a finite record referred to as the moving window. Tests are made on the validity of the parameter estimates before using the parameters in an on-line design process. The on-line design process is an algebraic mapping of the parameters of the model into primary control system feedback and feedforward gains. The mapping was selected to satisfy specific flying quality characteristics over the range of parameter variations expected. Results are presented from simulation studies on the identification algorithm made during the development of the system. Also, results from the F8-DFBW project simulation at the NASA langley Research Center are presented that indicate the overall performance of the control system in meeting the flying quality objectives of the design.     

重装空投系统的动力学建模与控制律设计

针对当前重装空投数学模型与实际系统存在偏差等问题,改进传统的分离体建模方法。将货物视作刚体考虑分析,修正了货物约束力的作用点,引入了牵引伞力作用方向,综合考虑了货舱地板角、摩擦系数等影响因素,提出更加精确的干扰力矩计算方法,建立更加贴近实际的重装空投动力学模型。设计了俯仰高度保持和速度保持控制律,并利用遗传算法选取了合适的控制律参数。仿真结果表明,所给出的控制方案能够有效地保持飞行轨迹和稳定飞机姿态。     

舰载机甲板停机位分配问题研究

舰栽机甲板停机位分配问题关系到航母飞行甲板作业的效率,合理的停机位分配对于提高甲板作业效率十分重要。对舰载机停机位分配问题进行了详细研究,以舰载机移动路径、加油路径以及挂弹路径总和最小为目标函数,建立了甲板停机位分配模型,利用贪心算法并结合模拟退火算法对模型进行了求解,仿真结果表明,该模型对停机位的分配合理。     

基于优化配平的机翼故障飞机飞行性能分析

分析飞机机翼故障对飞行性能的影响,对飞机故障后能够安全着陆或返航有着重要意义,飞机的机翼作为产生力和力矩的主要部件对飞行性能起着重要的作用。提出一种基于单纯形优化的机翼故障飞机飞行性能分析方法,建立机翼故障参数模型,根据飞机爬升转弯飞行条件进行优化配平计算,得到在不同状态下不同机翼故障的配平数据库,分析了故障后飞机的飞行性能。仿真结果表明所提算法的有效性。     

Nonlinear robustness analysis of flight control laws for highly augmented aircraft

In this paper, a novel hybrid optimisation algorithm is applied to the problem of analysing the robustness of a nonlinear flight control law in the presence of multiple variations in key aircraft parameters over continuous regions of the flight envelope. The analysis employs a typical nonlinear clearance criterion used by the European aerospace industry together with a simulation model of a high performance aircraft with a full authority control law which is gain scheduled over the flight envelope. The hybrid algorithm incorporates global (differential evolution) and local (sequential quadratic programming) optimisation algorithms to improve convergence properties and reduce computational overheads. The proposed approach is shown to have the potential to significantly improve both the reliability and efficiency of the industrial flight clearance process.     

飞机俯仰运动自抗扰控制器设计

提出了利用自抗扰控制器在大包线范围内设计飞机俯仰运动控制器的新方法．利用二阶自抗扰控制器补偿系统模型扰动和外扰，实现了纵向运动俯仰角变量的跟踪控制．自抗扰控制器直接依据飞机的非线性模型，符合飞机动力学模型摄动大的特点，在很大的包线范围内不需要改变控制器的结构和参数，简化了飞行控制律的设计过程．大包线范围内的仿真结果表明，系统具有良好的动态和稳态性能，控制器具有很强的鲁棒性，为解决大包线范围内的飞行控制问题提供了一种有效的新途径．     

飞行器特性曲线拟合与飞行仿真研究

随着计算机技术的高速发展,计算机仿真在航空航天领域得到了广泛的应用.飞行器的计算机飞行仿真计算涉及大量气动力特性和发动机特性参数,对这些参数采用两参数和三参数的曲线拟合方法替代过去的数值插值方法,减少了输入参数的数量,大大提高了仿真程序的代码效率和仿真实时性.基于这种方法拟合发动机和飞机气动特征的特性曲线,并利用Runge-Kutta方法建立了飞行方程的数值解算程序,对某型飞机起飞-巡航-降落过程进行了数值仿真.在此基础上设计了全程可视化程序,得到了全过程的舵面控制规律,为飞行模拟器的设计提供了有效的方法和手段.     

飞机飞行控制多目标优化研究

针对飞行控制系统单目标优化算法与飞行品质要求之间缺乏相关性,且物理意义不明确的缺点,提出了一种基于C*准则的模型参考飞行控制设计多目标优化方法。首先,使用飞行品质建立参考模型,保证所建立的参考模型符合期望飞行品质的要求。然后,通过模型跟随的方法,将飞行品质的要求引入多目标优化中,使得整个优化设计过程物理意义更加明确。最后,使用多目标NSGA-II对某型飞机纵向控制律设计进行数值仿真,结果显示提出的方法可以有效地提高控制器参数整定效率,整定结果满足期望的飞行品质要求。     

仿生扑翼“0”形轨迹机构的设计及气动力特性

针对仿生扑翼飞行器的驱动结构进行设计,提出了一种空间摇杆式的驱动机构与机翼扭转机构,实现机翼扑动过程中的"0"形空间运动轨迹.针对机翼的空间"0"字形运动,建立仿生飞行器气动分析模型,采用动网格与非定常数值计算方法,对机翼拍动过程中不同相位下的升阻特性进行分析,并通过空气动力效率与流场对比分析,得到不同参数条件下的气动效率,为仿生扑翼飞行器的设计及扑动模式的选择提供参考.通过气动力测量实验、台架姿态标定和外场飞行测试,验证了结构设计的合理性.     

基于雷达测距的飞行器交会对接误差补偿控制技术

为解决由视线倾角、视线偏角过大造成的飞行器对接存在误差的问题,实现飞行器交会轨迹的精准对接,提出基于雷达测距的飞行器交会对接误差补偿控制技术。建立空间参考坐标系,根据轨道根数计算结果,推导动力学状态方程,实现对飞行器交会对接过程中的动力学作用分析。按照雷达测距原理,计算飞行器的理论飞行时长及雷达装置作用距离,再联合相关参数指标,确定精度极限的取值范围,实现基于雷达测距的对接误差控制。在三坐标测量机结构模型中,定义飞行位姿拟合条件,再根据位姿误差求解结果,实现对误差参数的补偿修正处理,完成基于雷达测距的飞行器交会对接误差补偿控制方法的设计。对比实验结果表明,应用所提方法可以同时将视线倾角、视线偏角的取值控制在0°-45.0°的数值范围之内,能够较好解决飞行器错误对接的问题,符合精准对接飞行器交会轨迹的实际应用需求。     

空战战法训练系统目标机飞行轨迹实现

空战战法训练系统是运用仿真手段对指挥员和飞行员进行空战战法训练的虚拟系统,在该系统中,目标飞机的运动及其飞行轨迹生成是关系到系统成败的关键环节。首先分析确定了生成基于现有战法的目标飞机飞行轨迹的步骤;然后针对敌方飞机数据缺乏的实际状况,结合训练系统设计,在保证系统要求的前提下给出了考虑飞行极限参数的简化目标机仿真模型;根据现代空战特点选定了空战机动动作集,并设计了动作库;最后给出了根据时间步长推算的飞行轨迹简化计算模型。经实际检验,该模型可以有效地满足空战战法训练系统的需要。     

基于神经网络的故障飞机仿真

传统气动系数模型中，拟合法精度较差，插值法计算速度慢，且占内存多。利用神经网络一致逼近任意非线性连续函数的特性，训练具有一个三输入六输出的神经网络模型，建立故障飞机仿真系统。仿真结果和故障飞机自修复应用表明，文中所采用的神经网络建模方法是可行的。在自修复飞行控制系统研究中，为故障飞机建模所需大量故障状态气动系数数据处理提供一种新思路。     

飞机超机动状态动力学特征及对控制系统的挑战

超机动能力作为第四代战斗机的重要标志性特征,在近距空战中具有极其重要的作用.针对非线性非定常气动效应、强耦合和操纵器异构冗余等超机动状态飞机的基本动力学特征,分析了其非线性气动力/力矩、非定常迟滞效应、参数快时变、惯性耦合和推力矢量等因素给控制系统带来的挑战,总结了超机动飞机的非线性非定常气动力建模、飞行控制和控制分配的研究现状,给出了一种基于非线性补偿和气动力模型数据库的鲁棒解耦控制策略,为超机动飞行控制方法的工程应用提供了参考.     

基于试验点自动识别的飞行试验智能化监控技术

试验点作为飞行试验任务的最小组成单元,明确了试验机所要完成的任务及要求,是飞行效果评估的主要依据。深入分析试验机在完成不同试验点时的参数变化特征,结合领域专家人工识别的先验知识,提取影响试验点识别的关键参数及其变化规律。构建试验点识别知识库,设计试验点自动识别算法。结合飞行试验实时任务评估技术,开发基于试验点自动识别与智能评估的飞行试验实时监控系统,实现了从"智能化安全监控"到"智能化任务监控"的转变,有效提升了试验机的试飞效率。