超机动飞机动态逆-PID控制器设计

对超机动飞机在大迎角机动下的控制律进行设计,并完成相关仿真验证.通过引入推力矢量技术,建立带推力矢量的飞机非线性数学模型;采用奇异摄动理论,将飞机状态划分为快慢变换不同的同路,分别应用动态逆设计飞行控制律;并采用PID控制补偿由于未精确建模带来的系统逆误差;最后对所设计的控制律进行了机动指令飞行仿真.仿真结果表明,设计的控制律能在大迎角机动条件下控制飞机跟踪指令飞行,并保证闭环系统的稳定性.     

Application of neural networks for synthesizing flight control algorithms. I neural network inverse dynamics method for aircraft flight control

The application of artificial neural networks for aircraft motion control, in particular, for creation of nonlinear algorithms of the aircraft remote control system (RCS) is considered. Aircraft as a control object is represented as a multidimensional nonlinear dynamic system and nonlinear control methods are used to operate this system. The control loop is constructed using the method of inverse dynamics based on the feedback linearization principle. The nonlinear control law is represented as a neural network being learned (adjusted) by recorded or incoming measurements of motion parameters. Synthesis and testing of neural network control algorithms is performed with the fully nonlinear mathematical model of a maneuverable aircraft for three control channels. Simulation results of the closed system are presented.     

飞行力学和飞行控制试飞技术

为了适应高增益,全权限数字电传操纵系统飞行试验的需要,利用已研制成功的多台地面飞行模拟器和ＢＷ－１纵向,ＩＦＳＴＡ三自由度空中飞行模拟试验机,模型自由飞研究以及具有现代先进水平的机载数据采集记录和地面实时监控系统等设备和技术手段,进行了电传飞机的飞行品质和飞控稳定性等问题的研究,包括试飞输入设计,电传飞机飞行品质,电传飞控系统稳定裕度等。最后,提出了对下一代飞机飞行力学和飞行控制方面需要研究的试飞     

大机动飞机的非线性鲁棒控制律设计

采用非线性不确定系统的高增益控制建设设计方法,为某型大机动飞机在特定飞行条件下设计了鲁棒控制律,以跟踪期望的输出轨迹,并在不同飞行条件下进行了系统仿真研究。仿真结果表明,采用所设计的控制律,在不同飞行条件下,飞机均可同时完成较精确的纵向和侧向机动跟踪,说明控制律具有较好的鲁棒性。     

基于融合神经网络的航空发动机剩余寿命预测

航空发动机的性能退化是影响飞机飞行安全的重要因素。准确预测发动机的退化过程,对于飞机安全飞行具有重要意义。针对航空发动机剩余寿命预测问题,本文提出了一种将卷积神经网络和长短期记忆网络相融合的数据驱动模型。与常规使用单一的神经网络不同,所提出的融合模型结合了两种神经网络的优点,利用卷积神经网络提取数据中的空间特征并采用长短期记忆网络提取时间特征。实验结果证实,在寿命预测中,所提出的数据驱动模型与已有的方法相比,评分和均方根误差分别下降了32%和6.4%,因此,所提出的数据驱动模型可对数据中所包含的信息进行充分挖掘,其对航空发动机寿命预测精度较高,并具有良好的稳定性。     

Dynamics,stability, and control of a four-cable mount system for wind tunnel test

A four-cable mount system is proposed for full-model wind tunnel flutter tests, which may adjust the pitch and roll attitude of the aircraft scaled model and ensure that the model is not subjected to cable tension. The system provides sufficient support to simulate the free flight of the aircraft by applying appropriate spring stiffness and cable tensions. The proposed four-cable mount system is modeled based on Lagrange mechanics, and its dynamics equations consider aerodynamic effects. The singularity of the system and its bifurcation characteristics under flow conditions are analysed to determine the supercritical bifurcation phenomenon for different tension levels and distances from the front suspension point to the mass centre of the model. The mathematical expressions of the longitudinal flight stability of the cable mount system are derived by linearising the system dynamics equations using small perturbations. The influence of the cable tension, spring stiffness, suspension point position, and other factors on the flight stability of the aircraft are analysed. A feedforward control algorithm is proposed to minimize the total elastic potential energy of the system. The results show that the model is in the level flight state when the elastic potential energy of the four-cable mount system is minimized. A feedback control design method is proposed based on the Lyapunov stability theory to derive the closed-loop stability conditions. The system dynamics model that includes the aircraft rigid body model, flexible cables, pulleys, springs, aerodynamic model, and servo motor control is established using the flexible multibody dynamics method. A multibody dynamics solver and Simulink are used to simulate the attitude adjustment of the model in the wind tunnel and verify the supercritical bifurcation characteristics of the system and the effectiveness of the feedback and feedforward control.     

人工神经网络在飞机总体外形智能CAD中的应用

将人工神经网络应用于飞机总体外形智能ＣＡＤ中,针对现有方法的局限性,研究了参数神经网络,提出了一种综合考虑影响神经网络学习３个主要因素（权值、激励函数和拓扑结构）的ＷＡＦＳ学习算法,并研究了隶属函数的神经网络表达和基于神经网络的并行推理,给出了有关应用实例。     

Neural network modeling of flight control system

Modeling of angle tracking systems in the presence of actuator non-linearity such as angle, position and rate limits is a very significant and difficult task in the design and implementation of aircraft, target-tracking, and missile guided systems. A new recurrent neural network with time-delayed inputs and output feedback is used for the modeling of angle tracking systems, with emphasis on the neural network architecture, principles and algorithms. The neural network controller with modeling units for angle tracking is designed by using TMS320C25 processors. For time and size requirements, limited precision technology and look-up table technology are used in the design of the hardware and software systems. Given a set of input commands, the network is trained to control the system within the constraints imposed by actuators. The results show that the proposed networks are able to model the angle tracking system through learning without separate consideration of the non-linearity of actuators     

结冰对飞机动力学特性影响的分析方法及其进展

详细地介绍了常用的四种典型的结冰对飞机动力学特性影响的分析方法,即参量测算评估法、结冰影响参数法、神经网络气动建模法和动力学建模与仿真计算法,并讨论了各种分析方法的特点及其发展.     

贝叶斯正则化BP网络在机翼载荷分析中的应用

采用贝叶斯正则化与BP网络相结合的方法,构造了一个分析飞机机翼载荷的三层BP网络。贝叶斯正则化方法提高了BP神经网络的泛化能力,且能考虑非特征化的非线性影响。使用某型飞机对称机动和滚转机动的试飞实测数据作为载荷激励来训练神经网络,并用这个训练完的网络预测了该飞机机翼的飞行载荷。最后将神经网络预测结果与实测结果进行了比较,结果表明该方法能够准确地实现飞机机翼载荷预测,对新机研制和飞行试验有较高的参考价值。     

Integrated precision SAR targeting: a SAR targeting simulation

Operational deficiencies exist in the current ability to perform high resolution synthetic aperture radar (SAR) targeting for precision strike missions in difficult electronic countermeasure (ECM) and anti-aircraft environments. Increasingly sophisticated enemy defenses require that fire control information be derived from highly maneuverable aircraft trajectories rather than traditional straight-and-level flight. In addition, target area aspect information is needed to determine optimal attack approaches. These imaging and targeting conditions impose severe performance requirements on the sensor aircraft motion compensation system (MCS), and dictate the need for sophisticated algorithms to counteract ECM threats. This paper describes the development of a user friendly “Design Tool” for modeling and analysis of airborne radar system performance for SAR imaging and Precision SAR Targeting     

过失速大机动飞机的飞行控制律设计

对新一代带推力矢量的战斗机在大迎角过失速机动下的飞行控制律进行设计,并进行了机动指令飞行仿真。引进推力矢量技术,建立带推力矢量的飞机模型方程;采用奇异摄动理论,将控制回路分为两个快慢(内外)回路,对每个回路分别用动态逆方法进行飞行控制律设计;并采用结构奇异值μ综合和分析的方法对快(内)回路设计了鲁棒控制器;最后所设计的控制律进行了机动指令飞行仿真,仿真结果表明设计的过失速机动控制律良好。     

面向复杂构型飞机的非定常气动力建模与辨识

不论是现代高机动隐身战斗机的设计需求还是常规布局飞机的飞行动力学分析,深入研究大迎角飞行时的非线性非定常气动力模型都极其重要。基于纵向运动小振幅及大振幅强迫振荡试验数据,分析了常规稳定导数模型的准确性,并从导数模型出发发展了简化涡流和分离流时间迟滞效应的非定常气动力线性模型和非线性模型,最后应用风洞典型机动历程模拟试验验证了模型的有效性。结果表明：对于复杂构型高机动飞机模型,发展并改进的非线性微分方程模型可以准确预测飞机不同机动下的非定常气动力特性,具有较强的工程可行性。     

基于动态逆的综合非线性飞行控制方法

在解决非线性飞行控制问题中,动态逆控制方法已成为一种流行的控制方法.文中以动态逆控制方法为基础,使用神经网络控制与动态非线性阻尼控制综合的控制方法进行补偿,以提高非线性飞控系统的鲁棒性.在以某型推力矢量飞机为对象的仿真中,这种方法显示出很强的非线性控制能力和鲁棒性.     

T型尾翼布局的垂尾载荷测量技术

针对T型尾翼布局下平尾影响垂尾载荷的特点，提出了一套适用于T型尾翼布局的垂尾载荷实测试飞方法。该方法通过分析平尾载荷对垂尾的影响，设计平尾非对称校准加载工况，将其引入垂尾载荷方程建模，并使用该垂尾载荷方程测量了某型飞机型号合格审定试飞的垂尾飞行载荷。试验结果表明，载荷方程测量误差由5.3%降低到3.14%，平尾不对称弯矩载荷对垂尾弯矩影响显著，偏航机动严重受载状态时可达到垂尾弯矩的57.6%，滚转机动严重受载状态时可达到垂尾弯矩的61.9%。     

Design of Flight Control System for a Small Unmanned Tilt Rotor Aircraft

A tilt rotor is an aircraft of a special kind, which possesses the characteristics of a helicopter and a fixed-wing airplane. However, there are a great number of important technical problems waiting for settlements. Of them, the flight control system might be a critical one. This article presents the progresses of the research work on the design of flight control system at Nanjing University of Aeronautics and Astronautics (NUAA). The flight control law of the tilt rotor aircraft is designed with the help of an inner/outer loop control structure and an eigenstructure assignment algorithm on the basis of a proper mathematical model already verified by the wind tunnel tests. The proposed control law has been born out through the construction of the flight control system and the flight tests. Now, the flight tests are still underway on a prototype of small unmanned tilt rotor aircraft. The results have evidenced the credibility of the aircraft design and the effectiveness of the flight control system for the tilt rotor working in the helicopter mode. A full envelope flight test is planned to carry out further researches on the flight control law.     

飞机对称着陆多体动力学建模与实测验证

基于牛顿-欧拉多体动力学建模方法,建立了三体九自由度飞机对称着陆动力学模型.以某型双腔缓冲器起落架飞机为例,通过飞行实测不同状态下的起落架着陆动态载荷,仿真计算相应的着陆重量、着陆下沉速度及着陆姿态下的着陆动态载荷.验证分析结果表明,所建飞机对称着陆多体动力模型是有效的.     

Flight dynamics characteristics of canard rotor/wing aircraft in helicopter flight mode

The aerodynamic layout of the Canard Rotor/Wing(CRW) aircraft in helicopter flight mode differs significantly from that of conventional helicopters. In order to study the flight dynamics characteristics of CRW aircraft in helicopter mode, first, the aerodynamic model of the main rotor system is established based on the blade element theory and wind tunnel test results. The aerodynamic forces and moments of the canard wing, horizontal tail, vertical tail and fuselage are obtained via theoretical analysis and empirical formula. The flight dynamics model of the CRW aircraft in helicopter mode is developed and validated by flight test data. Next, a method of model trimming using an optimization algorithm is proposed. The flight dynamics characteristics of the CRW are investigated by the method of linearized small perturbations via Simulink. The trim results are consistent with the conventional helicopter characteristics, and the results show that with increasing forward flight speed, the canard wing and horizontal tail can provide considerable lift,which reflects the unique characteristics of the CRW aircraft. Finally, mode analysis is implemented for the linearized CRW in helicopter mode. The results demonstrate that the stability of majority modes increases with increasing flight speed. However, one mode that diverges monotonously,and the reason is that the CRW helicopter mode has a large vertical tail compared to the conventional helicopter. The results of the dynamic analysis provide optimization guidance and reference for the overall design of the CRW aircraft in helicopter mode, and the model developed can be used for control system design.     

飞机短周期运动参数的神经网络辨识

本文提出了一种用馈神经网络辨识飞机短周期运动参数的新方法。该方法的特点是不需要预先假定模型，只需要用获得的飞行数据训练一前馈馈神经网络，就可以用这个网络直接辨识参数的值。模拟飞行数据的仿真结果证明所提出的方法是有效的并且具有较好的鲁棒性。     

飞机积冰后若干飞行力学问题综述

回顾飞机积冰后若干飞行力学问题研究的历史与现状,着重介绍了积冰飞机气动数据的获取途径、积冰飞机飞行力学建模与飞行仿真、积冰对飞机稳定性和操纵性的影响以及积冰对飞机飞行性能的影响.在已有飞机积冰后飞行力学问题研究的基础上,提出了飞机积冰后飞行力学问题研究领域需要解决和关注的若干问题,包括通过数值模拟方法获取积冰飞机的气动数据、完善积冰对飞机气动导数影响的计算模型以及加强平尾失速方面的研究.今后需要进一步对模拟冰风洞、数值模拟方法和平尾失速进行研究,并获取更多实验数据.