大雨对飞机降落影响效应仿真研究与定量分析

为全面、定量分析大雨对飞机降落阶段的严重影响,选取波音737-300作为典型代表,首先对于降落阶段大雨造成的飞机性能损失进行了量级评估。然后重点针对降雨所导致的粗糙表面因素,利用CFD仿真方法和改进的湍流壁面函数,对于不同降雨强度下的波音737-300中段翼型气动性能进行了仿真模拟,给出了升阻力系数、失速攻角等定量结果,并与实验结果进行了对比。结果表明：大雨所导致的粗糙机翼表面将引起严重的气动性能损失。在降落阶段,对于波音737-300中段翼型而言,短时500毫米/小时降雨条件下,最大升力系数减少约28%,阻力系数平均增加达98.1%,失速攻角减小约5度。

Abstract：

Heavy rain might influence aerodynamic performance of an aircraft seriously, especially when it is landing. It requires an intensive investigation and quantitative analysis. Choosing Boeing 737-300 as the representative of aircraft, magnitude calculation for the penalty associated with severe rainfall was firstly made. Then the roughness factor was studied in detail using evolutional turbulence boundary function and CFD simulation tools. The aerodynamic character of Boeing 737-300 midspan airfoil was simulated under different rainfall environment. The quantitative results of lift-drag coefficients and stall angle were proposed and compared with experiment data. The results indicate that, the roughness surface caused by rainfall is most likely to cause significant aerodynamic penalties. For Boeing 737-300 midspan airfoil, when it is landing under severe rainfall of 500mm/hour over 30s periods, it could lead to the loss of maximum lift coefficient by about 28%, the decrease of stall angle by 5 and the increase of drag coefficient by 98.1%.     

基于UML的通用3D飞行仿真平台的设计与实现

一个能对不同飞行器进行仿真的综合性平台对飞行器建模和飞行控制算法设计等理论研究工作具有重要意义。采用基于UML的面向对象的程序设计方法,综合利用网络通信与3D视景仿真,数据库,模型库等技术,构建了基于局域网的分布式通用3D飞行仿真平台。通过为飞行器模型设计合适的接口,该平台可以适用于多种飞行器的仿真,大大减少了数据和代码的冗余,具有良好的飞行器通用性和功能扩展性。

Abstract：

Theoretical research on modeling and control of aircraft needs a platform to simulate and verify the correctness and accuracy.A distributed universal 3D flight simulation platform was designed based on UML Object Oriented modeling method,network communications,3D visual simulation,database and model base.This platform could be used for simulating various aircraft by well designed interface of aircraft models.The code and data redundancies are greatly reduced.The platform has a good aircraft universal availability and function augment ability.     

准坐标系下的弹性飞行器飞行动力学建模

结合有限元思想和拉格朗日方程推导了准坐标系下的弹性飞行器飞行动力学模型,与通常采用的平均轴系建模方法相比,该方法克服了变量难在相同坐标系下表示等缺点,而且该模型包含了自由度之间所有的耦合,能够更充分的反映刚性自由度与弹性自由度间的交叉耦合特性,更全面的从本质上体现飞行器结构动力学、空气动力学以及飞行动力学这种多学科之间相互影响的非线性飞行动力学特性。该动力学模型可用于弹性飞行器非线性稳定性分析、弹性飞行器飞行动力学与控制理论分析等。

Abstract：

As the frequency separation between the rigid body modes and the structural dynamics becomes tighter, the traditional aircraft flight mechanics treatment, there is, the rigid body approximation, may be not efficient. A complete coupled equation of motion for fully flexible aircrafts were derived, without any constraint relationship, which was done by employing Lagrange’s equations and the finite element method in terms of quasi-coordinates. This model includes automatically all six rigid-body degrees of freedom and elastic deformations, as well as the gravity, propulsion, aerodynamics, and control forces, in addition to forces of an external nature, such as gusts. Different from the modeling method based on ＂mean axes＂ coordinate system, the seamless integration was achieved by using the same reference frame and the same variables to describe the aircraft motions and the force acting on it, including the aerodynamic forces. The formulation is modular in nature, in the sense that the structural model, the aerodynamic theory, and the controls method can be replaced by any other ones to better suit different types of aircraft, provided certain criteria are satisfied.     

突发污染源散发特性辨识与仿真研究（英文）

在载人航天器、潜艇、飞机等密闭微环境中,如果发现有污染源存在,确定污染源的位置及其散发特性具有重要意义。笔者提出一种新型的浓度离散随机模型,在采用敏感性分析方法实现污染源定位后,利用隐式与显式卡尔曼滤波相结合的方法实现污染源散发特性的动态辨识与预测,同时完成空气污染物浓度预测。笔者采用蒙特卡罗仿真实验方法对一密闭空间进行了动态仿真研究,仿真结果表明提出的方法可以实现污染源散发特性的快速准确辨识,具有重要的应用价值。

Abstract：

In case of contaminants appear in enclosed spaces such as spacecraft,submarine,aircraft and so on,it is useful to find the contaminant source. A novel algorithm was proposed to identify contaminant source strength based on finite sensors. After having identified the source location by using the Sensitivity Analysis Algorithm （SAA）,this method built a new discrete concentration stochastic model,and combined implicit and explicit Kalman filter. Monte Carlo simulation was used in our experiment. The simulation results show that the new method could track and predict the source strength dynamically; meanwhile,it also could predict the distribution of contaminant concentration.     

基于视景通道的透镜成像过程仿真技术研究

针对计算机成像模型在使用过程中存在的不足,提出了对该模型进行完善与改进的方法。首先根据数字变焦原理,推导出放大倍率与视锥角的关系公式,实现了视景通道的变焦功能,该方法计算量小,效果逼真;其次,提出了一种镜头对焦过程的仿真方法,它充分利用粒子系统技术模拟对焦成像由模糊到清晰的过程,不仅获得更真实的图像效果,且满足实时性要求。上述改进后模型与实际摄像系统原理基本一致,增强了仿真系统视觉效果逼真性与沉浸感。由于该方法在工程上极易实现,可以在虚拟现实系统中广泛应用。

Abstract：

A way that could be improved was brought forward on the pin-hole camera model in allusion to the problems of the insufficient cue of depth. The relation formulas of the magnification and aspect angle were concluded according to the principles of digital zoom and the zooming function of visual channels was realized. The implementation of this method is simple and the effect is realistic. Besides,a simulation method for the course of adjusting focus was proposed,which brought blurry images into focus by particle system. Both vivid images and real time requirement could be achieved. The ameliorated model runs in the same way as the real camera system on the theory,thus enhancing the fidelity and immersion of visual effects. It is so easy to implement in project that this approach can be used universally in VR systems.     

基于混沌差分进化算法的飞机等效系统拟配研究

提出了基于Tent映射的混沌差分进化算法。以某飞机纵向短周期系统为例,首次研究了基于混沌差分进化算法的飞机等效系统的拟配,克服了一些传统的拟配算法存在的一些缺点。仿真结果表明,基于混沌差分进化算法拟配得到的等效系统满足等效系统拟配的各项要求和一级飞行品质的要求,取得了更好的拟配效果。证明该算法在飞机等效系统拟配中的有效性和高效性。

Abstract：

Chaotic differential evolution algorithm based on Tent map was introduced. Taking aircraft longitudinal short period system as an example,the analog-matching of the aircraft longitudinal equivalent system based on chaotic differential evolution algorithm was studied firstly and overcome the disadvantages of the conventional algorithms in the analog-matching of equivalent system. The simulation results show that the equivalent system by chaotic differential evolution algorithm is satisfied the various requirements in the analog-matching of equivalent system and the requirement of level 1 flight qualities,and has obtained better analog-matching results. The usefulness and high effectiveness of the chaotic differential evolution algorithm in the analog-matching of aircraft equivalent system is proved.     

飞行结冰后复杂系统动力学仿真与风险评估

综合考虑结冰后气动参数的变化和驾驶员动态特性,建立了结冰后人-机-环复杂系统非线性动力学仿真模型,仿真出结冰后迎角、俯仰角和俯仰角速度的变化趋势。提出了结冰恶化速率因子的概念,以迎角为临界参数,提出了通过冰型、结冰强度来判断失速的方法,提出了综合评估飞机在某一航段结冰后飞行风险的思路和对防冰系统最大允许故障率进行计算的方法,最后给出算例验证了该方法的实用性。     

Conceptual design and RCS performance research of shipborne early warning aircraft

In order to improve the survivability of the aircraft,conceptual design and radar cross section（RCS） performance research are done. The CATIA software is used to design the 3D digital model of the shipborne early warning aircraft, and some measures are taken to reduce the RCS characteristics of the early warning aircraft at the same time. Based on the physical optics method and the equivalent electromagnetic flow method,the aircraft＇s RCS characteristics and strength distribution characteristics are simulated numerically, and compared with the foreign advanced shipborne early warning aircraft. The simulation results show that under the X radar band, when the incident wave pitching angle is 0？, compared with the foreign advanced shipborne early warning aircraft, the forward RCS average value of the conceptual shipborne early warning aircraft is reduced to 24.49%, the lateral RCS average value is reduced to 5.04%, and the backward RCS average value is reduced to 39.26%. The research results of this paper are expected to provide theoretical basis and technical support for the conceptual design and the stealth design of the shipborne early warning aircraft.     

A Model-Based, Aspiration-Led Decision Support System NY-IEDSS

An Al-aided simulation system embedded in a model-based, aspiration-led decision support system NY-IEDSS is reported. The NY-IEDSS is designed for mid-term development strategic study of the Nanyang Region in Henan, China, and is getting beyond its prototype stage under the decision maker's (the end user) orientation. The integration of simulation model system, decision analysis and expert system for decision support in the system implementation was reviewed. The intent of the paper is to provide insight as to how system capability and acceptability can be enhanced by this integration. Moreover, emphasis is placed on problem orientation in applying the method.     

A Model-Based, Aspiration-Led Decision Support System NY-IEDSS

An AI-aided simulation system embedded in a model-based, aspiration-led decision support system NY-IEDSS is reported. The NY-IEDSS is designed for mid-term development strategic study of the Nanyang Region in Henan, China, and is getting beyond its prototype stage under the decision maker's (the end user) orientation. The integration of simulation model system, decision analysis and expert system for decision support in the system implementation was reviewed. The intent of the paper is to provide insight as to how system capability and acceptability can be enhanced by this integration. Moreover, emphasis is placed on problem orientation in applying the method.     

机翼结冰后人-机系统动态特性仿真与风险评估

机翼结冰导致气动特性改变,为了定量分析机翼结冰导致的飞行风险,提出了利用人-机系统数值仿真数据进行概率评估的方法.考虑结冰对临界迎角、升阻特性等的影响,通过建立非线性动力学仿真模型和特殊情况下驾驶员操纵副翼偏转模型,实现了机翼结冰后的人-机系统动态仿真.分析了非指令控制滚转不正常现象,并通过影响因子的概率分布模型,最终实现了飞行风险概率评估.     

结冰对飞机飞行动力学特性影响的仿真研究

采用一种计算飞机结冰后气动系数和气动导数的工程方法,引入几个结冰参数,建立结冰后飞机飞行动力学模型。根据这些参数计算了飞机结冰后阻力系数以及典型气动导数的变化,并计算了结冰前后飞机的飞行包线;同时对结冰前后飞机的纵向、横侧动稳定性以及升降舵、副翼和方向舵阶跃操纵响应进行仿真计算。这种方法除了简单、物理概念明显、耗费少之外,采取将外界结冰条件与飞机本体分开处理的思路,具有广泛的适应性。结冰参数值随时间变化,可为实时监控结冰影响提供数据。     

结冰条件下飞机全包线模态特性分析方法

针对飞机带冰飞行时全包线范围内飞行品质评估问题, 提出一种结合自适应拟配初值计算与时域等效系统拟配对整个包线内的典型模态参数快速计算方法。建立了典型的人-机-环系统模型, 通过数值仿真得到飞机对于方向舵倍脉冲操纵的响应数据, 在分析时域响应数据特征的基础上, 提出自适应计算横航向等效系统拟配初值的方法, 解决了拟配初值的敏感性问题。运用时域等效系统拟配法, 分别获取了某型飞机干净构型及不同结冰严重程度时, 整个包线范围内横航向模态参数特性, 进而从整体的角度量化了结冰对飞机飞行品质的影响。仿真结果表明，所提方法在全包线范围内具有较好的适应性，为快速分析飞行器纵横向典型模态特性提供了新的思路，具有较好的工程应用前景。     

超机动飞行自抗扰控制律设计与仿真

提出了一种利用自抗扰控制器算法设计超机动飞行控制系统的新方法。根据自抗扰控制器可以动态补偿系统模型扰动和外扰的特点,在超机动飞行快回路和慢回路中引入自抗扰控制器,实现了快变量和慢变量的动态解耦控制。直接针对飞机超机动飞行条件下的强耦合、强非线性模型进行控制律设计,符合超机动飞行控制的非线性、模型摄动大、模型不精确等特点,在很大的包线范围内不需要改变控制器的结构和参数,简化了设计过程。大包线范围内的大迎角机动仿真结果表明,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,为解决超机动飞行控制问题提供了一种新的途径。     

某型飞机失速尾旋模拟训练系统关键技术研究

针对国内某型飞机失速尾旋模拟训练需求,研制了某型飞机失速尾旋模拟训练系统。系统由多通道球幕视景系统、半实物仿真座舱以及操纵力控制加载系统等组成,采用分布式仿真技术,构建了逼真的人在回路模拟训练环境。针对失速尾旋仿真,对多源气动数据进行了综合处理,构建了大迎角非定常气动力模型,采用大载荷数字电动控制加载技术进行失速尾旋交变力和抖振特性仿真,实现了人在回路的失速尾旋模拟训练。     

Study on robust terrain following control

1.INTRODUCTION Terrainfollowing(TF)isanimportanttechnology formodernaircraftsuperlowaltitudepenetration flights.Iteffectivelymakesuseofinterferenceand deadzonesinenemydefensesystemscreatedbystray groundwavesandterrainundulations,raisingaircraft survivalcapabilities.Manymethodsareusedinair craftsuchasadaptiveanglemethodinF 111andB 1, templatemethodin“Tornado”and“Mirage2000” etc.TFtechnologyisalsousedincruisemissilessuch as“Tomahawk”.Aerodynamicnonlinearitiesandthe uncertaintiesof…     

超机动飞行的非线性鲁棒自适应控制系统研究

针对飞机模型中存在气动参数不确定性以及外界干扰等影响因素,设计了一种超机动飞行的非线性鲁棒自适应控制系统。控制系统设计过程中,模型不确定性和外界干扰由RBF神经网络在线补偿,控制律及神经网络权值自适应律由反步法得到。解决了系统中控制增益矩阵未知,同时存在外界干扰情况下的鲁棒飞行控制系统设计,并证明了闭环系统所有信号有界,系统跟踪误差和神经网络权值估计误差指数收敛到有界紧集内。对所研究的飞行控制系统进行了过失速Herbst机动仿真,结果验证了该系统在过失速机动条件下具有良好的控制性能。     

一种基于环境预报数据的阵风建模方法

针对现有飞行器仿真试验自然环境模型,研究环境预报数据转换和处理方法;基于随机波浪理论,建立二元阵风紊流数学模型,并研究该模型的仿真建模方法;基于Davenport谱建立基于环境预报数据的阵风紊流模型,并引入到飞行器六自由度数学仿真试验中,得到阵风紊流对于飞行器飞行状态的影响情况。试验结果表明,阵风紊流对于飞行器攻角影响较大,对于飞行高度影响较小,利用阵风紊流模型开展飞行器航迹仿真试验切实可行。     

气象保障中基于遗传算法的航迹规划仿真

飞行器在执行任务过程中,需要根据三维空间和时间的气象信息变化、障碍物、威胁等信息以及飞行器自身的机动性能限制,计算出飞行航迹.主要通过基于遗传算法的航迹规划理论和应用MM5模式输出产品（风场、积冰、颠簸）信息,进行航迹路径的规划仿真验证与分析,给出了具有实际工程应用价值的飞行航迹.