排序方式: 共有8条查询结果,搜索用时 15 毫秒
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Chi Pei Chen Zongji Zhou Rui Wei Chen 《中国航空学报》2007,20(5):443-451
未来空天飞行器跨空天两域飞行,要求有较高的自主性以适应由故障和环境变化带来的不确定因素。针对空天飞行器的不确定性,提出了自主控制重构方案。研究了线性模型的时变控制效益的估计方法,提出并证明了效益矩阵可估计的充分条件,给出了相应的算法并证明了其收敛性和对噪声的鲁棒性;提出了基于线性规划和模糊逻辑的控制分配算法,通过冗余效应器实现了不确定条件下的自主控制重构。系统集成和仿真结果分析验证了方案和算法的有效性。 相似文献
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Abnormal Shape Mould Winding 总被引:1,自引:0,他引:1
Fu Hongya Wang Xianfeng Han Zhenyu Fu Yunzhong 《中国航空学报》2007,20(6):552-558
为解决网格化芯模的缠绕问题,本文提出了复合材料面片缠绕机理;接着详细分析了面片缠绕过程中的芯模凹曲面上纤维滑线和架空现象,应用微分几何曲面理论和空间几何理论,提出判据及其解决方案;最后,针对飞机发动机进气道的缠绕成型,编制缠绕控制程序并进行相应的实验,验证了面片缠绕方法的可行性。 相似文献
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Convergence Analysis of the Numerical Solution for Cathode Design of Aero-engine Blades in Electrochemical Machining 总被引:1,自引:0,他引:1
Li Zhiyong Niu Zongwei 《中国航空学报》2007,20(6):570-576
As a main difficult problem encountered in electrochemical machining (ECM), the cathode design is tackled, at present, with various numerical analysis methods such as finite difference, finite element and boundary element methods. Among them, the finite element method presents more flexibility to deal with the irregularly shaped workpieces. However, it is very difficult to ensure the convergence of finite element numerical approach. This paper proposes an accurate model and a finite element numerical approach of cathode design based on the potential distribution in inter-electrode gap. In order to ensure the convergence of finite element numerical approach and increase the accuracy in cathode design, the cathode shape should be iterated to eliminate the design errors in computational process. Several experiments are conducted to verify the machining accuracy of the designed cathode. The experimental results have proven perfect convergence and good computing accuracy of the proposed finite element numerical approach by the high surface quality and dimensional accuracy of the machined blades. 相似文献
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飞机的大气传感器是获得飞机外部大气参数的重要的测量仪器,如果大气传感器自身精度不够,或者由于布置不合理引起的误差,就会引起飞行危险。为了验证气动设计的布局方案,选出传感器位置比较优化的方案,得到机头静压值随迎角变化不变的区域,同时总结出民机大气数据传感器布局设计验证的风洞试验方法。通过低速测压风洞试验和缩比传感器(风标和七孔探针),测量得到大气传感器不同布局位置的气动特性。结果表明:大气传感器的布局位置对测量结果影响相当重要;试验结果与计算结果符合良好,满足气动设计要求。 相似文献
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Huang Lin Wan Min Chi Cailou Ji Xiusheng 《中国航空学报》2007,20(6):564-569
The age forming technology, characterized by huge spring-backs, has been developed to manufacture large integral wing-skin panel parts, which necessitates devising a method of predicting spring-backs. A 7B04-T7451 aluminum alloy creep test in tension is accomplished at 155 ℃, and the creep curves are obtained. The material constants of the mechanism-based creep constitutive equations are determined through experiments. The age forming process and the spring-backs of 7B04 aluminum alloy plates are analyzed using the commercial finite element software ABAQUS. The effects of plate thickness and forming time on spring-backs are researched. The spring-backs decrease with the increase of plate thickness and forming time. The test results verify the reliability of the finite element method (FEM) analysis. 相似文献
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