模糊控制方法及其在飞控中的应用

对于较大的飞行包线，飞机对象的参数变化剧烈，采用常规控制方法往往不能保证在较大飞行包线范围内均取得良好的控制效果，基于此，提出了一种新型的自组织模糊控制方法，该对系统内部参数的剧烈变化具有很强的适应性，然后对飞机飞行控制系统的控制律设计进行了研究。用所提出的模糊控制方法设计了部分控制律，最后以某型国产飞机对象，采用飞机六自由度非线性仿真模型，在一个较大的飞行包线范围内，进行了飞行仿真，取得了良好的     

Gaseous cavity at the base of an underwater projectile

The problem of the behavior of the gaseous cavity which is formed at the base of an underwater launched projectile is treated using different approaches. Asymptotic analysis is used to yield expressions for similarity parameters and a simplified hydrodynamic model of the initial stretching phase. A laboratory facility is described, in which launches can be simulated and analyzed by means of pressure measurements and high speed visualizations. Complete calculations are also performed using a numerical “Volume of Fluid” model solving the unsteady Navier-Stokes equations. Results from the three approaches are presented and compared during the cavity stretching phase. Finally, the thermodynamic aspects of the problem are examined.     

FINITE DIFFERENCE MODEL FOR SIMULATION OF DENSIFYING CARBON-CARBON COMPOSITES BY CHEMICAL VAPOR INFILTRATIONP ROCESSES

ＮｏｍｅｎｃｌａｔｕｒｅｓＡ０—ｃｏｅｆｉｃｉｅｎｔｏｆｔｈｅＡｒｈｅｎｉｕｓｅｑｕａｔｉｏｎＣ（ｎ）—ｈｙｄｒｏｃａｒｂｏｎｃｏｎｃｅｎｔｒａｔｉｏｎｉｎｕｎｉｔ（ｎ）（ｍｏｌ／ｃｍ３）Ｃ０—ｈｙｄｒｏｃａｒｂｏｎｃｏｎｃｅｎｔｒａｔｉｏｎａｔｅｘ...     

Nonlinear Aeroelastic Response of High-aspect-ratio Flexible Wings

The aeroelastic analysis of high-altitude, long-endurance (HALE) aircraft that features high-aspect-ratio flexible wings needs take into account structural geometrical nonlinearities and dynamic stall. For a generic nonlinear aeroelastic system, besides the stability boundary, the characteristics of the limit-cycle oscillation (LCO) should also be accurately predicted. In order to conduct nonlinear aeroelastic analysis of high-aspect-ratio flexible wings, a first-order, state-space model is developed by combining a geometrically exact, nonlinear anisotropic beam model with nonlinear ONERA (Edlin) dynamic stall model. The present investigations focus on the initiation and sustaining mechanism of the LCO and the effects of flight speed and drag on aeroelastic behaviors. Numerical results indicate that structural geometrical nonlinearities could lead to the LCO without stall occurring. As flight speed increases, dynamic stall becomes dominant and the LCO increasingly complicated. Drag could be negligible for LCO type, but should be considered to exactly predict the onset speed of flutter or LCO of high-aspect-ratio flexible wings.     

石英半球谐振子精密成型技术

石英半球谐振陀螺以其轻质、低功耗、长寿命、高可靠、应用精度范围宽、成本低等优势，引起了惯性技术界的瞩目。半球谐振陀螺的核心器件——石英半球谐振子的成型技术是当前的研究重点。经不断试验和摸索，以范成球面弹性展成为基础，通过均衡磨削原则、磨头最大包络原则和三阶段37道工序的精细优化工艺流程，较好地实现了高精度微应力硬脆石英谐振子异形薄壁件的成型，形成了专用的结构成型中心，为石英半球谐振陀螺的核心半球谐振子球壳成型开创了一条可行途径。     

应用摄动法确定飞机的模态特性

应用摄动法将飞机四阶线化方程降为二阶方程，导出确定飞机纵向长，短周期模态和模航向滚转，螺旋，荷兰滚模态近似解析解。     

带座舱飞船高超声速粘性绕流的分离形态及流场结构分析

通过求解薄层近似的Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程，数值模拟了带座舱飞船高超声速粘性绕流，首次系统地给出了攻角为５°、１０°、２０°、３０°和４０°情况下的物面分离形态、横戴面流线形态、纵剖面流线形态以及旋涡沿涡轴的演变形态。分析和比较表明，本文采用数值可视化方法给出的流场拓扑结构与相应的拓扑规律完全吻合。在飞船后体流场横截面流线中，本文发现了稳定的极限环流态，该极限环涡心处沿涡轴方向的速度是超声速     

AN ANALYSIS OF PROPELLER LIFTING－LINE THEORY BY MATCHED ASYMPTOTIC EXPANSIONS

ＡＮＡＮＡＬＹＳＩＳＯＦＰＲＯＰＥＬＬＥＲＬＩＦＴＩＮＧ－ＬＩＮＥＴＨＥＯＲＹＢＹＭＡＴＣＨＥＤＡＳＹＭＰＴＯＴＩＣＥＸＰＡＮＳＩＯＮＳＣｈｅｎＺｅｍｉｎ；ＰａｎＪｉｅｙｕａｎ；ＷｕＬｉｙｉ（ＩｎｓｔｉｔｕｔｅｏｆＦｌｕｉｄＭｅｃｈａｎｉｃｓ，Ｂｅｉ...     

粘性超声速绕体流动的有限谱法计算

首先推导出粘性可压缩流体动力学基本方程组在广义坐标下矢通量分裂的一般形式，并将有限谱ENO格式用于求解超声速流动问题。通过典型算例，验证了这一格式的精度和稳定性。然后进行了圆柱和机翼超声速绕流的数值模拟，得到了与实验和其他计算相符的结果。这表明有限谱法不单具有精度高，应用灵活等多方面的优点，而且突破了传统谱方法全域性的局限，可以成功地应用到一般形状流场可压缩流动的数值计算中。     

飞机容冰技术的研究进展

回顾了国内外在飞机结冰方面的研究情况。在此基础上．介绍了近年来国外在飞机容冰技术研究中的最新设想——智能防冰系统(SIS)，对SIS研究中涉及的结冰气动模型进行了探讨，从飞行安全角度出发．给出了SIS中结冰飞行包线保护系统的基本原理及实现方法。