绕飞监测小卫星姿轨联合自适应控制研究

针对小卫星近距操作过程中轨道和姿态控制问题,建立了小卫星相对轨道和姿态的误差动力学模型。采用相对轨道和姿态联合控制策略,并考虑小卫星作业过程中质量和转动惯量的不确定性,设计了自适应输出反馈控制律,并证明了其稳定性。最后以对圆轨道目标星近距离环航为例,根据作业任务和姿态指向要求,设计了小卫星相对轨道和姿态的期望运动,应用所提出的控制策略及相应的控制律进行了数值仿真。结果表明,系统跟踪误差能够较快收敛,说明了控制策略的有效性。     

跟踪弹道导弹时预警卫星姿态前馈协同控制

基于角动量守恒定理,推导了跟踪弹道导弹时,具有活动部件的预警卫星姿态前馈协同控制。该控制算法基于角动量守恒方程估计红外相机运动产生的角动量扰动以及为抑制该扰动所需的期望飞轮转速,将期望飞轮转速与实际转速的偏差作为前馈信号加入到传统控制系统中,推导出预警卫星姿态前馈控制模型。最后通过数值仿真验证了控制方法,仿真结果与理论分析具有很好的一致性。并且该控制方法简单、可靠,能够适应卫星在轨实时控制。     

阻力方向舵在无尾飞机飞行控制中的应用

阻力方向舵在无尾飞机上得到广泛的应用。以一种无尾飞机为例,讨论了阻力方向舵舵效的非线性、耦合性等基本特性,并说明了阻力方向舵张开后对飞机整体的影响。给出了阻力方向舵在无尾飞机航向增稳、空速控制、作为复合舵使用三个方面的应用实例和仿真结果,说明了阻力方向舵在无尾飞机飞行控制应用中存在的一些问题及其解决方法。     

V: SEA LEVEL: Benefits of GRACE and GOCE to sea level studies

The recently published Third Assessment Reports of the Intergovernmental Panel on Climate Change have underlined the scientific interest in, and practical importance of past and potential future sea level changes. Space gravity missions will provide major benefits to the understanding of the past, and, thereby, in the prediction of future, sea level changes in many ways. The proposal for the GOCE mission described well the improvements to be expected from improved gravity field and geoid models in oceanography (for example, in the measurement of the time-averaged, or ‘steady state’, ocean surface circulation and better estimation of ocean transports), in geophysics (in the improvement of geodynamic models for vertical land movements), in geodesy (in positioning of tide gauge data into the same reference frame as altimeter data, and in improvement of altimeter satellite orbits), and possibly in glaciology (in improved knowledge of bedrock topography and ice sheet mass fluxes). GRACE will make many important steps towards these ‘steady state’ aims. However, its main purpose is the provision of oceanographic (and hydrological and meteorological) temporally-varying gravity information, and should in effect function as a global ‘bottom pressure recorder’, providing further insight into the 3-D temporal variation of the ocean circulation, and of the global water budget in general. This paper summaries several of these issues, pointing the way towards improved accuracy of prediction of future sea level change. This revised version was published online in August 2006 with corrections to the Cover Date.     

基于加速度计和角速率陀螺的超小无人直升机姿态控制系统

设计了一种基于加速度计和角速率陀螺的超小型无人直升机姿态控制系统;由卡尔曼滤波算法融合加速度计和陀螺数据,实时估计最优的直升机姿态信号;根据最优的姿态反馈信号,飞行控制系统采用参数自整定的模糊PID控制方法得到舵机控制信号,从而实现了超小型无人直升机的姿态控制。     

商用飞机翼尖装置减阻机理及其发展与应用

推导了商用飞机诱导阻力公式,给出经典的诱导阻力表达式。对翼尖装置发展和演变历史进行了梳理,分析了翼梢小翼的减阻机理。从端板作用、耗散翼尖涡等5个方面分析了翼梢小翼对商用飞机飞行性能的影响,在此基础上提出了翼梢小翼的设计参数和设计原则。最后研究了应用于不同型号商用飞机的翼梢小翼的特点和最新进展。研究结果表明,商用飞机使用翼梢小翼能够显著降低诱导阻力,增加升阻比并提高燃油经济性。同时,商用飞机翼梢小翼正向着智能变形结构方向发展,以实现不同飞行任务阶段的性能最优化。     

某型机旋翼斜梁折叠地面模拟试验台拖动系统的设计与应用

本文主要介绍了某型机旋翼—斜梁折叠地面模拟试验台拖动系统方案的设计、系统关键设备和部件匹配设计以及在功能试验和耐久性试验中的应用。     

An Overview of the Lunar Crater Observation and Sensing Satellite (LCROSS)

The Lunar Crater Observation Sensing Satellite (LCROSS), an accompanying payload to the Lunar Reconnaissance Orbiter (LRO) mission (Vondrak et al. 2010), was launched with LRO on 18 June 2009. The principle goal of the LCROSS mission was to shed light on the nature of the materials contained within permanently shadowed lunar craters. These Permanently Shadowed Regions (PSRs) are of considerable interest due to the very low temperatures, <120?K, found within the shadowed regions (Paige et al. 2010a, 2010b) and the possibility of accumulated, cold-trapped volatiles contained therein. Two previous lunar missions, Clementine and Lunar Prospector, have made measurements that indicate the possibility of water ice associated with these PSRs. LCROSS used the spent LRO Earth-lunar transfer rocket stage, an Atlas V Centaur upper stage, as a kinetic impactor, impacting a PSR on 9 October 2009 and throwing ejecta up into sunlight where it was observed. This impactor was guided to its target by a Shepherding Spacecraft (SSC) which also contained a number of instruments that observed the lunar impact. A?campaign of terrestrial ground, Earth orbital and lunar orbital assets were also coordinated to observe the impact and subsequent crater and ejecta blanket. After observing the Centaur impact, the SSC became an impactor itself. The principal measurement goals of the LCROSS mission were to establish the form and concentration of the hydrogen-bearing material observed by Lunar Prospector, characterization of regolith within a PSR (including composition and physical properties), and the characterization of the perturbation to the lunar exosphere caused by the impact itself.     

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     

解耦模糊控制方法及在飞控中的应用

以某型飞机为对象，控制飞机纵向定高恒速飞行。由于模型是非线性的，采用模糊控制，并具有两个输入两个输出系统的模糊控制方法进行研究，找出了解耦控制规律，并结合ＰＩＤ控制器综合构成了模糊ＰＩＤ控制器。仿真结果显示控制过程时间短、超调量小，振荡小，为飞行控制提供了一种新方法。     

联接翼布局直接升力控制特性的初步研究

本文对联接翼气动布局的直接升力控制特性进行了初步的探索。通过前、后机翼上升降舵面的同向偏转组合所产生的直接升力，与相应的正常布局相比较，不仅显示了飞机优异的气动性能：增加了最大升力系数和升力线斜率，改善了失速特性，提高了纵向静稳定性，而且明显改善了ΔＣｙ、Δｎｙ、ΔＨ、ωｚ等参数对操纵输入的瞬态响应品质，给飞机提供独立的姿态或轨迹控制的非同寻常的运动模态。头部鸭翼的增加进一步提高和改善了联接翼布局的直接升力特性。     

Satellite range scheduling with the priority constraint: An improved genetic algorithm using a station ID encoding method

Satellite range scheduling with the priority constraint is one of the most important problems in the field of satellite operation.This paper proposes a station coding based genetic algorithm to solve this problem,which adopts a new chromosome encoding method that arranges tasks according to the ground station ID.The new encoding method contributes to reducing the complexity in conflict checking and resolving,and helps to improve the ability to find optimal resolutions.Three different selection operators are designed to match the new encoding strategy,namely random selection,greedy selection,and roulette selection.To demonstrate the benefits of the improved genetic algorithm,a basic genetic algorithm is designed in which two cross operators are presented,a single-point crossover and a multi-point crossover.For the purpose of algorithm test and analysis,a problem-generating program is designed,which can simulate problems by modeling features encountered in real-world problems.Based on the problem generator,computational results and analysis are made and illustrated for the scheduling of multiple ground stations.     

微分控制在飞机和船舶系统中的应用

本文叙述了微分控制在飞机和船舶控制系统中的作用,举出了一些实际应用的微分控制方法,并简述了这些方法的优缺点。     

国内飞参使用及发展趋势设想

飞参数据是调查飞行事故的重要依据,在飞机研制/试飞、训练、状态监控、视情维修等方面起到十分重要的作用。随着飞参数据记录系统的发展,飞参数据的应用前途广阔。因此,深入挖掘飞参的应用价值,对确保飞行安全、提高部队战斗力有着相当重要的作用。本文分析了国内外飞参应用研究现状,并对其发展趋势作了展望。     

改进直接多重打靶算法及其应用

直接多重打靶算法是求解最优控制问题很有效的方法之一。通过仅假设出节点处的控制变量值．使该算法在求解最优控制问题时更方便，收敛更快。利用改进算法求解了飞机在风切变中着陆和敏捷性管理系统的优化设计问题。结果表明．改进算法能较好地求解一类受约束最优控制问题，对奇异最优控制问题也能较好求解。     

高速开关阀在起落架半主动控制中的应用研究(英文)

To select or develop an appropriate actuator is one of the key and difficult issues in the study of semi-active controlled landing gear. Performance of the actuator may directly affect the effectiveness of semi-active control. In this article, parallel high-speed solenoid valves are chosen to be the actuators for the semi-active controlled landing gear and being studied. A nonlinear high-speed solenoid valve model is developed with the consideration of magnetic saturation characteristics and verified by test. According to the design rule of keeping the peak load as small as possible while absorbing the specified shock energy, a fuzzy PD control rule is designed. By the rule controller parameters can be self-regulated. The simulation results indicate that the semi-active control based on high-speed solenoid valve can effectively improve the control performance and reduce impact load during landing.