基于Riccati方程的离散容错控制系统设计

基于离散系统的Ｒｉｃｃａｔｉ方程，提出一种对传感器失效具有完整性的离散控制系统的设计方法，给出了完整性设计方法的设计步骤，并用设计实例验证了该方法的有效性．该方法还可推广用于执行器失效的情况．     

直升机涡环状态试验数据处理研究

采用神经网络误差反向传播算法,以旋翼涡环状态试验数据为基础,研究了桨叶负扭度对直升机涡环状态特性的影响,分析了负扭度变化对旋翼扭矩、拉力平均值及脉动幅度的影响。计算结果表明,神经网络模型能够准确预测桨叶负扭度对直升机涡环状态的影响。     

自适应DBF与空间谱估计

讨论了自适应数字波束形成(DBF)技术和超分辨空间谱估计技术,并提出了一种基于信号协方差矩阵特征分解的时-空二维信号高分辨谱估计算法。以上技术应用于相控阵雷达系统,可以精确获得多个运动目标的方位信息和多普勒信息。文章最后给出了计算机模拟结果。     

一种TASIMM-UKF导弹状态估计方法

为了提高对机动导弹状态估计的精度和速度,提出了一种三轴分离IMM-UKF(TASIMM-UKF)滤波算法。将导弹运动状态按坐标轴方向进行三轴分离,并基于CV,CA和CJ模型集,采用无迹卡尔曼滤波器并行估计导弹三轴状态信息,有效地解决了导弹不同运动轴间的模型竞争问题。仿真结果表明,该方法能有效提高状态估计精度,缩短了估计时间,对复杂大机动目标状态估计具有良好的性能。     

An improved approach for rainfall estimation over Indian summer monsoon region using Kalpana-1 data

In this paper, an improved Kalpana-1 infrared (IR) based rainfall estimation algorithm, specific to Indian summer monsoon region is presented. This algorithm comprises of two parts: (i) development of Kalpana-1 IR based rainfall estimation algorithm with improvement for orographic warm rain underestimation generally suffered by IR based rainfall estimation methods and (ii) cooling index to take care of the growth and decay of clouds and thereby improving the precipitation estimation.     

AADL在航天器控制系统设计中的应用研究

以某型号航天器为例提出了一种使用体系结构分析和设计语言(AADL,architecture analysis & design language)分层次建模的方法,建立控制系统软件及软件与硬件之间的交互模型.采用状态自动机方式描述串口通信协议,以便分析模型.     

磁选态单束铯束管束光学参数的模拟计算和设计

为提高铯束管跃迁信号强度,在束光学参数设计中,用蒙特卡罗方法模拟计算铯原子通过率和未跃迁比例。通过改变模拟计算中的束光学参数,分析铯原子通过率、未跃迁比例和倍增器首极电流的变化趋势,得到了主要束光学参数的合理取值范围。在铯束管实际装配和试验中使用束光学参数设计结果,有效地增加了倍增器首极电流。     

A fast pulse phase estimation method for X-ray pulsar signals based on epoch folding

X-ray pulsar-based navigation (XPNAV) is an attractive method for autonomous deep-space navigation in the future. The pulse phase estimation is a key task in XPNAV and its accuracy directly determines the navigation accuracy. State-of-the-art pulse phase estimation techniques either suffer from poor estimation accuracy, or involve the maximization of generally non-convex object function, thus resulting in a large computational cost. In this paper, a fast pulse phase estimation method based on epoch folding is presented. The statistical properties of the observed profile obtained through epoch folding are developed. Based on this, we recognize the joint prob-ability distribution of the observed profile as the likelihood function and utilize a fast Fourier transform-based procedure to estimate the pulse phase. Computational complexity of the proposed estimator is analyzed as well. Experimental results show that the proposed estimator significantly outperforms the currently used cross-correlation (CC) and nonlinear least squares (NLS) estima-tors, while significantly reduces the computational complexity compared with NLS and maximum likelihood (ML) estimators.     

Multi-state autonomous drilling for lunar exploration

Due to the lack of information of subsurface lunar regolith stratification which varies along depth, the drilling device may encounter lunar soil and lunar rock randomly in the drilling process. To meet the load safety requirements of unmanned sampling mission under limited orbital resources, the control strategy of autonomous drilling should adapt to the indeterminable lunar environments. Based on the analysis of two types of typical drilling media (i.e., lunar soil and lunar rock), this paper proposes a multi-state control strategy for autonomous lunar drilling. To represent the working circumstances in the lunar subsurface and reduce the complexity of the control algo-rithm, lunar drilling process was categorized into three drilling states:the interface detection, initi-ation of drilling parameters for recognition and drilling medium recognition. Support vector machine (SVM) and continuous wavelet transform were employed for the online recognition of dril-ling media and interface, respectively. Finite state machine was utilized to control the transition among different drilling states. To verify the effectiveness of the multi-state control strategy, drilling experiments were implemented with multi-layered drilling media constructed by lunar soil simulant and lunar rock simulant. The results reveal that the multi-state control method is capable of detect-ing drilling state variation and adjusting drilling parameters timely under vibration interferences. The multi-state control method provides a feasible reference for the control of extraterrestrial autonomous drilling.     

Spectroscopy peculiarities of thermal plasma of electric arc discharge between electrodes with Zn admixtures

Plasma of the free burning electric arc between Ag–SnO₂–ZnO composite electrodes as well as brass electrodes were investigated. The plasma temperature distributions were obtained by Boltzmann plot method involving Cu I, Ag I or Zn I spectral line emissions. The electron density distributions were obtained from the width and from absolute intensity of spectral lines. The laser absorption spectroscopy was used for measurement of copper atom concentration in plasma. Plasma equilibrium composition was calculated using two independent groups of experimental values (temperature and copper atom concentration, temperature and electron density). It was found that plasma of the free burning electric arc between brass electrodes is in local thermodynamical equilibrium. The experimental verification of the spectroscopic data of Zn I spectral lines was carried out.