直接力控制飞机时域和频域特性分析

直接力控制是主动控制技术是主动控制技术要实现的主要功能之一。此功能的实现无论对民有飞机还是军用飞机都有重大的意义。现介绍ＤＦＣ飞机时域的频域特性分析的意义和基本方法，并讨论ＤＦＣ飞机飞行品质规范的制订，依据，品质等级的评定方法，最后以ＹＦ－１６ＣＣＶ飞机为算例进行了仿真分析，结果表明，对ＤＦＣ飞机进行时域和频域分析，能够较全面地了解ＤＦＣ飞机的各项性能；利用频域特性，可以方便地评定了ＤＦＣ飞机飞行     

F—16飞机大迎角飞行特性分析

采用六自由度全量运动方程和三通道飞行控制系统模型，使用时域动态响应的方法，研究了Ｆ－１６飞机在大迎角下飞行的深失速特性和尾旋特性，并对尾旋进入和改出的机理进行了探讨。通过分析研究可午出结论：Ｆ－１６飞机具有深失速特性，若进入深失速后，可用先拉杆后推杜操纵方法改出；Ｆ－１６飞机进入尾旋的主要原因是航向自转和偏航、滚转气动交感；在改出尾旋过程中，方向舵操纵力矩、航向静不稳定力矩、偏航惯性交感力矩对制止     

F—16飞机数字式飞控系统的改进试飞

本文旨在详述对Ｆ－１６飞机数字式飞控系统的几次更改情况。进行这些更改是为了提高Ｆ－１６飞机的抗偏离能力和改出特性。文中还介绍了目前生产的Ｆ－１６飞机４ ＤＦＬＣＳ。试飞计划的目的是确定ＤＦＬＣＳ的哪一次更改能够充分提高其性能，以保证它能够用于现役Ｆ－１６ＤＦＬＣＳ飞机。     

飞机能量机动性及其计算

首先介绍了能量机动性产生的背景和发展。然后给出了能量机动性的计算方法，还介绍了Ｅ－Ｍ图和全局能量机动性图的绘制方法，以及如何用它们来衡量战斗机空战性能，并以Ｆ－１６飞机和ＭＩＧ－２９飞机为例，绘制了Ｅ－Ｍ图及全局能量机动性图。这一研究为国内新一代战斗机设计的评估提供了一种理论研究方法和计算手段。     

军用飞机的生存力设计

飞机生存力是一种设计特性，本文论述了军用飞机生存力的设计内容和方法。并以A－10A、UH－60A为例分析了所采用的主要技术措施，可供飞机生存力设计时参考。     

F—117A飞行试验计划

Ｆ－１１７Ａ被认为代表了航空科研人员最早在开发隐身作战飞机方面所做的全部设计研究。洛克西德高技术发展公司成功地降低了ＳＲ－７１飞机的雷达特征，并且在Ｕ－２飞机上研究了其它低可探测技术，可是这两种情况都不是其主要的设计目标。Ｆ－１１７Ａ不建党的形状是这些目标的直接结果，空气动力学，稳定性和操纵工程师们的主要工作就是要把员失减少到最小限度并提供满意的飞行特性。     

F-22飞机生存性设计分析

战斗生存性是现代收音机设计的一个重要内容，Ｆ－２２是最先进战斗机的典型代表。介绍收音机战斗自下而上的基本概念和自下而上性增强的设计技术，分析Ｆ－２２飞机的生存性设计特点暨特征信号减缩、战术应用和综合航空电子系统，说明生存性增强对飞机作战效能的影响，得出Ｆ－２２飞机在可用的技术条件下是一个平衡的、作战效能高的成功设计。     

飞机平衡状态的优化计算方法

分析了飞机定常飞行时平衡状态的基本特性，提出一种平衡状态及平衡面的优化计算方法，并以F－16飞机为模型，对其常规飞行时的平衡状态参数在推力矢量控制下迎角定常飞行时的平衡面进行了计算。仿真结果表明，该方法具有较好的收敛性、稳定性，在飞机定常飞行的配平计算、用分支突变理论分析大迎角非线性特性时平衡面的计算以及推力矢量控制的分析计算中，有广泛的应用价值。     

台湾地区 空战武器真实作战能力

目前.台湾空军拥有３００多架性能相对先进的作战飞机（Ｆ－１６Ａ/Ｂ Ｂlock２０ “幻影”２０００－５型和IDF ），它们与９０架Ｆ－5Ｅ改进型战斗机搭配 ．形成了一支第二． 三代共存． 高中低档搭配， 具有较强空中拦截和一定对地攻击能力的空中力量。本文客观而真实地介绍以上几种作战飞机的实际作战能力，供航空爱好者参考。     

增强超大黄蜂飞机的大迎角机动性和尾旋改出特性

早期的作战评估表明，由于太注重抗偏离特性，对原有Ｆ／Ａ－１８超大黄蜂飞机的一些战术性能进行了折衷。为了解决这些问题，在试验项目的工程和制造发展阶段，在经费和进度的限制范围内，使飞机效能达到期望值，从而为飞行员进行正式的作战评估提供高效能的飞机，波音、海军工程小组和综合试验小组共同努力，在工程和制造发展项目的实施中，对Ｆ／Ａ－１８Ｅ／Ｆ大迎角机动性操纵性的几项指标进行了改进。本文对这样两种设计问题进行了叙述：首先，对飞机进行设计以便增强大迎角滚转效能，争取满足对下一代飞机所面临的威胁的要求，然而增强超大黄蜂飞机的抗偏离特性，会使作战飞行员在关键的近距空战机动中不能取得要求的性能；其次，尽管对称外挂载荷尾旋改出特性是可以接受的，但是如果可能，希望改进横向重量在各种不对称情况下的尾旋改出特性。虽然这不是一项设计要求，     

“T”型尾翼飞机的深失速特性研究

应用时间历程法讨论了“Ｔ”型尾翼飞机的深失速开环特性，分析了气动力矩特性和升降舵操纵规律对深失速改出特性的影响。建立了深失速闭环特性计算数学模型，分析了驾驶员数学模型参数变化对深失速特性的影响。研究结果表明，气动力矩特性，升降舵操纵规律和驾驶员模型参数的变化对“Ｔ”型尾翼飞机的深失速改出特性有显著的影响。     

Bifurcation analysis and stability design for aircraft longitudinal motion with high angle of attack

Bifurcation analysis and stability design for aircraft longitudinal motion are investigated when the nonlinearity in flight dynamics takes place severely at high angle of attack regime. To predict the special nonlinear flight phenomena, bifurcation theory and continuation method are employed to systematically analyze the nonlinear motions. With the refinement of the flight dynamics for F-8 Crusader longitudinal motion, a framework is derived to identify the stationary bifurcation and dynamic bifurcation for high-dimensional system. Case study shows that the F-8longitudinal motion undergoes saddle node bifurcation, Hopf bifurcation, Zero-Hopf bifurcation and branch point bifurcation under certain conditions. Moreover, the Hopf bifurcation renders series of multiple frequency pitch oscillation phenomena, which deteriorate the flight control stability severely. To relieve the adverse effects of these phenomena, a stabilization control based on gain scheduling and polynomial fitting for F-8 longitudinal motion is presented to enlarge the flight envelope. Simulation results validate the effectiveness of the proposed scheme.     

Loss-of-Consciousness&Spatial Disorientation Auto-Recovery System

A G-induced loss-of-consciousness (GLOC) and spatial disorientation auto-recovery system has been developed and tested on the Advanced Fighter Technology Integration (AFTI)/F-16 aircraft. The pilot controls the operation of this system by entering an MSL altitude and manually arming the system. Engagement conditions of the auto-recovery maneuver are controlled by aircraft speed, altitude, attitude, and the set recovery altitude and do not depend upon any determination of pilot physiological condition. Initiation of the recovery maneuver is preceded by visual and aural warnings which continue until the pilot resumes control. The pilot always has the capability to override or disengage the autorecovery maneuver. This system, as developed on the AFTI/F-16, is directly and quickly applicable to other analog or digital flight control systems such as found in the F-16 or F-18. This system provides the pilot protection from ground collision in most air-to-air training environments.     

应用于超级电容储能系统的双向DC/DC变换器混沌控制方法研究

超级电容储能系统(SCESS)主要通过对双向DC/DC变换器进行控制来快速平抑直流母线电压的波动。为了抑制控制过程中所产生的一些分岔和混沌现象,提出了一种应用于SCESS的混沌控制方法。分析了该方法的控制原理,并根据非线性动力学理论建立了双向DC/DC变换器的离散迭代模型;然后设计了一种能够自动调节补偿斜率的混沌控制信号;最后对该信号作用下的异步切换函数和同步切换映射式进行了数值求解,从而绘出系统分叉图。通过仿真和试验证明,该方法能够有效抑制SCESS的分岔和混沌现象,提高了系统的稳定工作范围和动态响应速度。     

非线性转子轴承系统Hopf分叉点的计算

针对非线性转子－轴承系统的具体特点,引入扩展方程方法,对采用长轴承模型的刚性Ｊｅｆｆｃｏｔｔ转子系统增加约束方程,消除系统分叉的奇异性,使系统的Ｈｏｐｆ分叉点在定解条件下得以准确求解。同时,为验证该方法,在相同条件下对该系统进行数值仿真研究。结果表明,扩展方程方法可以快速准确地确定转子－轴承系统的Ｈｏｐｆ分叉点,分析结果为定性控制转子的稳定运行状态提供了理论依据。     

固定翼双旋弹动力学分岔特性分析

针对一种滚转稳定的固定翼双旋弹,对其非线性动力学进行了分岔特性分析,并在此基础上研究了各系统参数对其动力学分岔特性的影响。根据固定翼双旋弹非对称的特点,通过数值计算方法研究其飞行过程中平衡点随同向鸭翼安装角的变化规律,通过系统的分岔图得知系统具有三组稳定平衡点,其中只有一组平衡点为理想可行的稳定平衡点,因此需限定同向鸭翼安装角的范围以使固定翼双旋弹保持稳定飞行。在此基础上针对固定翼双旋弹弹道修正组件周期旋转和转角固定两种工作模式,通过各系统参数下的系统分岔图总结了固定翼双旋弹结构及气动力参数对其动力学系统分岔特性的影响。仿真结果表明,固定翼双旋弹的各气动力参数及飞行速度均对系统的分岔特性具有较大影响,应合理选定这些系统参数以使其具有良好的气动特性。     

Sensor/actuator failure detection in the Vista F-16 by multiplemodel adaptive estimation

Multiple model adaptive estimation (MMAE) is applied to the Variable-In-flight Stability Test Aircraft (VISTA) F-16 flight control system at a low dynamic pressure flight condition (0.4 M at 20000 ft). Single actuator and sensor failures are addressed first, followed by dual actuator and sensor failures. The system is evaluated for complete or “hard” failures, partial or, “soft” failures, and combinations of hard and soft actuator and sensor failures. Residual monitoring is discussed for single and dual failure scenarios. Performance is enhanced by the application of a modified Bayesian form of MMAE, scalar residual monitoring to reduce ambiguities, automatic dithering where advantageous, and purposeful commands     

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.     

Stability analysis of digital linear flight controllers subject to electromagnetic disturbances

High intensity electromagnetic radiation has been demonstrated to be a source of computer upsets in commercially available digital flight control systems. Such upsets can degrade the quality of the control signal ranging from a perturbation error over a few sample periods to a permanent error mode or computer failure. Under these conditions, the primary concern of the control engineer is to insure that the closed-loop system remains stable. A stochastic disturbance model and a set of associated stability assessment tools are introduced for determining stability robustness of a nominal closed-loop system subject to electromagnetic disturbances. The focus is primarily on night control applications, but the methodology is suitable for any application where highly reliable digital control is needed. The technique is demonstrated on a simple test example and on a stabilizing controller for the longitudinal dynamics of the AFTI/F-16 aircraft.