非线性系统的全局线性输出反馈镇定

考虑了利用线性输出反馈全局镇定一类不确定非线性系统的问题.已有线性输出反馈控制中三角型约束条件被推广到了非三角型条件.构造了一个线性高增益观测器和一个耦合的线性高增益控制器,并利用增益尺度变换的方法,证明了闭环系统的全局稳定性.仿真结果说明该方法的有效性.     

一类有理递归序列的全局稳定性

研究了下列差分方程平衡点的全局渐近稳定性、全局吸引性以及周期性xn＋1=α-xn-k/xn,n=0,1,…,式中;x-k,x-k＋1,…,x0为任意实数,α为一实数,k为一整数.     

铷吸收半导体激光稳频光波长标准研究

介绍了用铷吸收光谱法对半导体激光器进行稳频,通过对包括半导体激光驱动源、稳频器、吸收室、光路等系统的优化设计,达到具有高信噪比微分误差信号,从而大大提高了半导体激光器稳频锁定灵敏度和长期稳定性。采用文中介绍的方法建立的光波长标准系统,其波长的测量重复性、稳定性可满足当前和将来很长一段时间光波长计校准的需要。     

带末端攻击角约束连续有限时间稳定制导律

针对制导武器末端攻击角约束与末端弹道尽可能平直的要求,应用有限时间控制方法,设计了具有末端攻击角约束的连续有限时间稳定制导律,使闭环制导系统在有限时间内视线角速度收敛到零和视线角收敛到期望值。通过非线性控制系统的有限时间稳定齐次性理论对该制导律进行了分析,证明了闭环制导系统的视线角速度和视线角全局有限时间稳定特性,并基于有限时间Lyapunov稳定性理论给出了闭环制导系统有限停息时间的表达式。在实例应用仿真中,比较了该制导律与最优制导律的制导性能,检验了该制导律在不同作战任务下的制导效果。仿真结果证实了该制导律的有效性和鲁棒性。     

Dual attitude and parameter estimation of passively magnetically stabilized nano satellites

The attitude determination capability of a nano satellite is limited by a lack of traditional high performance attitude sensors, a result of having small budgets for mass and power. Attitude determination can still be performed on a nano satellite with low fidelity sensors, but an accurate model of the spacecraft attitude dynamics is required. The passive magnetic stabilization systems commonly employed in nano satellites are known to introduce uncertainties in the parameters of the attitude dynamics model that cannot easily be resolved prior to launch. In this paper, a batch estimation problem is formulated that simultaneously solves for the attitude of the spacecraft and performs parameter estimation on the magnetic properties of the magnetic materials using only a measurement of the solar vector. The estimation technique is applied to data from NASA Ames Research Center's O/OREOS nano satellite and the University of Michigan's RAX-1 nano satellite, where clear differences are detected between the magnetic properties as measured before launch and those that fit the observed data. To date this is the first known on-orbit verification of the attitude dynamics model of a passively magnetically stabilized spacecraft.     

基于气体动理学方法的多尺度稳态热辐射计算

随着航空发动机燃烧室内燃气温度的提升,高温区域的热辐射问题将会变得更为重要,同时由于高温气体辐射导致辐射特性的剧烈变化,将会呈现出多尺度的现象,增加了辐射计算的难度。文章通过稳态离散统一气体动力学格式（SDUGKS,Steady Discrete Unified Gas Kinetics Scheme）的思路实现稳态辐射问题的求解,SDUGKS格式通过特征线差分离散的方法实现单元界面的重构,通过某种迭代格式来实现单元数据的更新,这一过程实现了对网格内部的辐射特性的有效模拟,该过程可适用于任何具体的辐射尺度。因此就可以在任意网格条件下实现多尺度问题的计算。文章引入了修正的延迟修正法（Deferred-correction,DC）实现单元数据更新,对单一尺度和多尺度问题进行了计算,在单一尺度问题中,验证了SDUGKS格式求解稳态辐射问题的正确性,进一步构造多尺度问题进行求解,论证了SDUGKS在多尺度问题计算中的渐近保持性质和准确性。     

Libration and end body swing stabilization of a parallel partial space elevator system

This paper studies the libration and stabilization of a parallel partial space elevator system in circular orbits. The system is made up of two paralleled partial space elevators, each of which consists of one main satellite, one end body and a climber moving along the tether between them. The libration characteristics of the elevator are studied through numerical analysis by a new dynamic model, and a novel control strategy is proposed to stabilize the swing of the end body by projecting the climber speeds only. Optimal control method is used to implement the new control strategy in the case where the climbers move in opposite direction. The simulation results validate the effectiveness of the proposed control strategy whose application will neither sacrifice the transport efficiency nor exacerbate libration significantly.     

轨道机动时考虑延迟的卫星姿态稳定控制方法

轨道机动时,测量与传输延迟,以及偏心推力对卫星姿态的持续扰动,造成传统的姿态稳定控制方法控制性能下降。为了克服这些问题,设计了对外扰与状态同时估计的闭环-开环预测器。在外扰力矩定常的假设下,给出了此种估计器对状态与外扰的预测都收敛的判定准则。利用估计出的外部扰动前馈补偿推力偏心干扰力矩,同时利用预测出的系统状态设计状态反馈控制器。通过求解两个代数Riccati方程,设计最优状态反馈增益和预测器增益。这种简单的前馈反馈结构具有良好的工程可实现性,同时仿真结果显示,该方法可以有效克服延迟和干扰的影响,提高卫星轨道机动时本体姿态稳定精度。
     

一个有理递归序列解的稳定性条件研究

方程xn 1=(a bx2n)/(c x2n-k),a,b,c∈[0,∞),a b>0,n,k∈{0,1,2…}的解有很多有意义的性质.Li证明了当a相似文献   

有限对象集合的同时镇定与分组设计

研究了有限对象集合同时镇定的基本理论问题。证明了４个对象可同时镇定的充要条件是存在４个稳定的多项式同时满足２个多项式方程。如果找到的多项式仅能满足其中一个方程,那么一定存在２个具有公分母或公分子的控制器使得它们分别同时镇定其中的２个对象。讨论了问题的可解性条件,进而给出了３个对象的分组与同时设计算法。