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161.
162.
为了使高超声速飞行器能够跟踪预定指令,针对其严反馈模型提出了基于收缩理论的控制方法。由于高度和速度相对独立,因此分开设计控制器。控制器设计过程中,以基于反步法的收缩理论为核心,对于模型中不确定项利用自适应进行在线识别;引入动态面对虚拟控制输入进行求导,并利用收缩下的奇异摄动分析降阶系统,可以证明降阶前后状态误差间的偏差及滤波误差有界。采用此方法,可证明系统状态半全局收敛,跟踪误差及自适应估计误差有界。 相似文献
163.
Witold Rohm 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
The GNSS signal along its more than 20,000 km line of sight is bended, attenuated and delayed. These effects are results of the Earth’s atmosphere, and Sun radiation. Amongst all mentioned effects the one considered in this paper is a signal phase delay in troposphere. 相似文献
164.
The issue of mesh-dependence emerges when the conventional continuum damage model is applied to handling the softening behavior. In order to circumvent the mesh-dependence, the non-local theory is introduced into the conventional damage model and the finite element formulas are derived for two-dimensional gradient-enhanced damage model. A new element is proposed in which the basic unknown quantities are displacement, non-local equivalent strain and the gradient of non-local equivalent strain. The element and constitutive equation proposed in this article are added to the finite element software ABAQUS through user subroutine UEL. Numerical results show that the gradient-enhanced damage model can eliminate the mesh-dependence and is effective for dealing with the issue of softening behavior. 相似文献
165.
针对飞机直流供电系统中直流设备工作情况,本文利用FPGA双进程有限状态机方法控制A/D转换器,快速准确采样多路信号。用模糊理论的建议语言规则,结合PIC单片机的控制优势,从而解决飞机直流供电系统设备故障预测报警。 相似文献
166.
As multi-discipline coupling and components interference often affect the aircraft configuration decision-making and analysis during conceptual design process, this article presents an approach of multidimensional game theory based on aircraft components to deal with this problem. The idea is that the configuration decision-making process is regarded as the game for different disciplines and technologies, and the aircraft components are players. The payoff function with highest total gain means that according to the game protocols and multidimensional theory, the optimal aircraft configuration within the strategy set will be chosen. The decision-making model is applied to conceptual design process of the high altitude long endurance (HALE) unmanned aerial vehicle (UAV) based on the assessment of technological risk. The obtained optimum configuration is quite consistent with the current HALE UAV development trends. Thus, taking into account the coupling and interference factors, the multidimensional gaming model based on aircraft components will be an effective analysis method in the decision-making process of aircraft optimum configuration. 相似文献
167.
词汇学习是我国大学生英语学习的重点以及难点,传统的机械性背记方法耗时多,收效少。就提高我国大学生英语词汇学习效率这一问题,从认知语言学的原型理论出发,为我国大学生学习词汇提供了更科学,更高效的学习方法。 相似文献
168.
Data fusion algorithm based on state and attribute parameter 总被引:1,自引:0,他引:1
Aquestionthathasbeenconcernedformanyyearsinthemultitargettrackingfieldishowtoreducethecomputationalcomplexityofdataassociatio... 相似文献
169.
陈祖贵 《中国空间科学技术》1989,(6)
本文介绍UDU~T 分解滤波算法;用工程师容易理解的方法重新推导时间修正和量测修正滤波公式,并给出标准通用的UDU~T 分解滤波子程序。本算法子程序已实际用于工程估计器中。本算法具有高的数字稳定性。作为UDU~T 分解滤波算法理论和工程应用之间桥梁的本通用标准子程序具有良好性能,使用方便,极易推广应用。 相似文献
170.
H.J. Völk E.G. Berezhko L.T. Ksenofontov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,41(3):473-476
For the case of Tycho’s supernova remnant (SNR), we present the relation between the blast wave and contact discontinuity radii calculated within the nonlinear kinetic theory of cosmic ray (CR) acceleration in SNRs. It is demonstrated that these radii are confirmed by recently published Chandra measurements which show that the observed contact discontinuity radius is very close to the shock radius. Therefore a consistent explanation of these observations can be given in terms of efficient CR acceleration which makes the medium more compressible. 相似文献