In-Flight Parity Vector Compensation for FDI

The performance of a failure detection and isolation (FDI) algorithm applied to a redundant strapdown inertial measurement unit (IMU) is limited by sensor errors such as input axis misalignment, scale factor errors, and biases. A techique is presented for improving the performance of FDI algorithms applied to redundant strapdown IMUs. A Kalman filter provides estimates of those linear combinations of sensor errors that affect the parity vector. These estimates are used to form a compensated parity vector which does not include the effects of sensor errors. The compensated parity vector is then used in place of the uncompensated parity vector to make FDI decisions. Simulation results are presented in which the algorithm is tested in a realistic flight environment that includes vehicle maneuvers, the effects of turbulence, and sensor failures. The results show that the algorithm can significantly improve FDI performance, especially during vehicle maneuvers.     

球形重力场下的视线动力学方程

以交会对接问题为背景,建立了球形重力场下的视线动力学方程,其简化形式可以描述平面重力场下的相对运动。该方程直接描述了视线参数和机动策略之间的关系,可广泛应用于相对运动问题的机动策略研究。     

远程教学原理与课件制作方法

课件是一种 Ｗｅｂ 文档,所有 Ｗｅｂ 文档技术均可用于制作课件。本文阐述了远程教学系统的原理和课件实现方法,并实现了一个远程教学课件———讲授 Ｉｎｔｅｒｎｅｔ 的基本知识和 Ｈ Ｔ Ｍ Ｌ 语言。     

高速撞击充气压力容器前壁损伤数值模拟

针对空间碎片超高速撞击充气压力容器前壁损伤问题,应用非线性动力学分析软件AUTODYN采用拉格朗日方法对球形弹丸撞击球形压力容器前壁穿孔进行了数值模拟研究。在建模过程中通过对容器壁内侧施加压力边界条件来模拟由于内充气体的作用在容器壁内产生的应力场,并通过与试验结果的比较验证了数值模拟方法的有效性。在此基础上针对容器的内充气体压力、球形弹丸直径及撞击速度对充气压力容器前壁穿孔的影响进行了研究。结果表明:在一定的气体压力下,气体压力对压力容器前壁穿孔直径与穿孔形态的影响可以忽略不计;而撞击速度及弹丸直径对穿孔直径及穿孔形态有着较大的影响,当撞击速度大于3km/s时,撞击穿孔边缘开始有裂纹产生,并且穿孔直径与裂纹直径随着弹丸直径及撞击速度的增加而增大。利用压力容器前壁穿孔的数值模拟结果进行计算可以得出当容器受到撞击速度大于3km/s的弹丸撞击后比撞击速度不大于3km/s时更易发生破坏。     

低压铸造的计算机控制系统

低压铸造的控制得到人们的日趋重视。本文讨论的是以单片机为基础的低压铸造计算机控制系统。     

Evaluating Sensor Orientations for Navigation Performance and Failure Detection

A study of the constraints imposed by the choice of particular orientations of redundant inertial sensors upon navigation system performance and the detection and identification of sensor failures in fault-tolerant inertial measurement units is presented. Figures of merit are derived for systematically evaluating alternative sensor orientations. The volume of the ellipsoid associated with the covariance matrix of estimation errors is used to rank sensor orientations in terms of navigation performance. Distance measures commonly used in hypothesis testing are used to rank sensor orientations in terms of the detectability of sensor failures. The application of these results is illustrated for configurations of four 2-degree-of-freedom gyroscopes.     

FDI Performance of Two Redundant Sensor Configurations

A geometrical interpretation of the generalized likelihood test (GLT) approach to sensor failue detection and isolation (FDI) is provided, and analytical expressions are derived to evaluate FDI performance parameters of interest. These results are used to determine the FDI performance which can be achieved when various FDI decision strategies are applied to two redundant sensor configurations: a conical array of five single degree-of-freedom sensors and a dodecahedron array of six single degree-of-freedom sensors.     

电磁作动器动态特性对隔振性能的影响

对电磁作动器的动态特性及其对主动隔振系统振动传递率的影响进行了分析研究.振动传递率不仅受作动器动态特性的影响,而且还与反馈变量的选取有关,这对振动主动控制系统的反馈设计具有指导意义.     

后射空空弹的总体构想与控制律研究

讨论了空空导弹后射的工程实现问题.阐明了后射的必要性和其现实技术基础;分析了后射弹工程实现存在的问题(主动段的姿态静稳定性问题);提出了解决该问题的综合技术方案,依据该方案建立的系统模型,进行了系统设计及仿真.结果阐明,实现空空导弹后射是可能的.     

关于制导问题的闭合形式解

研究了系统惯性对制导问题闭合形式解的影响,并获得了解析形式的解。此解表明不考虑惯性问题的解只是本闭合形式解在大视线距条件下的一种特殊形式。本解也适合小视线距,视线角速度不稳以及造成脱靶的原因等,都得到了反映。分析结果可用来研究比例导引系数、系统惯性对脱靶量的影响。