基于姿态敏感器的高轨道卫星自主导航方法的研究

为了解决未来高轨道卫星的自主运行问题，本文提出了一种基于姿态敏感器的同步轨道卫星自主导航方法，作为卫星自主运行的先决条件。在整个测量系统中，以含有摄动项的HILL方程为状态方程，同时由姿态敏感器给出的空间三个星体相对卫星本体方位，推导出量测方程，证明了测量子系统的能观性，并给出了简化了的推广Kalman滤波算法。仿真表明：该方法具有收敛速度快、精度较高的特点，是一种可行的同步轨道卫星自主导航方法。     

高速磁浮轨道检测系统地面处理软件的设计

为了解决高速磁浮轨道检测数据量大、处理难度大、处理程序不方便一线工人操作的问题,对数据处理类软件的设计方法进行了研究,分析了高速磁浮轨道检测各数据对象在处理工具与处理流程方面的差异性,设计了基于LabVIEW、Matlab及Python混合编程的高速磁浮轨道检测系统地面处理软件;该软件利用LabVIEW简单快捷的软件交互界面开发,结合Matlab强大的计算能力和Python在图像处理领域的成熟算法,快速完成工程软件的开发工作,实现大量数据的“一键式处理”,解决实际工程需求;同时将不平顺处理模块、磁场处理模块及图像处理模块单独封装为可执行文件进行调用,极大地提高了代码运行的稳定性和可维护性,便于进行功能扩展。     

基于GNSS的门式起重机姿态实时纠偏方法

随着我国现代工业的不断发展,大型门式起重机的应用也越来越多。在实际生产中,大型门式起重机常常会因为轨道严重磨损、操作不当等原因造成偏斜甚至倒塌,从而造成人员伤亡与巨大的经济损失。现有的检测方法采用编码器等传感器,通常有累计误差无法消除,行走机构静止时偏斜无法检测等缺陷。针对这一问题,采用GNSS导航定位技术,通过相对定位算法与坐标转换,实时解算出起重机械的三维姿态信息。沪东中华造船厂实际运行数据表明,基于GNSS导航技术的纠偏方法平均误差小于原有编码器纠偏方法,并且能够有效地在门式起重机行走机构停止时检测出主梁偏斜与俯仰角。     

基于UM的磁浮列车-轨道梁耦合振动仿真程序开发

基于大型通用多体动力学仿真分析平台Universal Mechanism(UM),开发用于磁浮列车 轨道梁耦合振动仿真的专用程序UM Maglev,其中：磁浮列车设置为多刚体模型,弹簧和阻尼器的刚度和阻尼视为线性或非线性力元;轨道梁设置为三维铁木辛柯梁模型,或从外部有限元软件导入模态分析结果;轨道线路包含平面和纵断面曲线、超高和轨面随机不平顺;悬浮和导向系统控制采用PID模型;多体动力学系统微分 代数方程求解采用Park刚性稳定法。该程序可用于考察磁浮列车的曲线通过性能、运行平稳性和乘坐舒适度,研究悬浮/导向气隙与磁浮控制系统参数优化,分析轨道梁在动态电磁力作用下的振动响应。     

一种新的遗传算法交叉算子及其在GNSS星座选择中的应用

针对全球导航卫星系统（GNSS）星座选择的需要,分析了多星座卫星导航定位系统选星问题的数学描述形式,根据选星问题的实质要求,将选星问题转换为单约束组合优化问题。而在采用遗传算法求解诸如选星求解类组合优化问题时,由于其对1基因（或0基因）的数量有特别的约束要求,已有的一些交叉算子不能满足该约束要求。针对基因数约束条件,提出了一种新的交叉算子——变异交叉,新的交叉算子仅以1基因或0基因为交换对象实现交叉操作来产生原始后代、以变异作为辅助方式来实现后代的合法化。实验结果表明,所提出的交叉算子能有效应用于遗传算法实现多星座卫星导航定位系统选星求解,且运算量较少,可以实现简单、快速求解,满足实时选星要求。     

GNSS姿态测量接收机性能分析

利用同源射频平台实现了一种全球导航卫星系统（ GNSS）姿态测量的接收机,接收机各射频电路相同且使用同一个晶振驱动,各射频通路之间有相同的信号处理特性。可以将射频通路分为主射频通路和从射频通路,主射频通路实现信号的捕获与跟踪,从射频通路利用差分相位鉴别器完成测量观测量提取。与传统使用独立接收机实现载波差分测向不同,主射频通道进入跟踪状态后立即输出观测量,无需检测载波半周跳变,实现快速姿态测量。利用GNSS姿态测量接收机、Novatel接收机以及惯性导航系统进行了跑车实验,实验结果表明：姿态测量接收机具有更好的载波测量输出能力,姿态测量精度和商业接收机相当。     

电推进系统在静止轨道卫星平台上应用的关键技术

在未来静止轨道平台上应用电推进系统是我国航天事业发展的必然趋势。将氙离子电推进系统（XIPS）应用于静止轨道卫星平台,除了要解决电推力器本身的问题之外,还要在系统应用方面做大量工作。以该静止轨道卫星对电推进系统的需求为基础,从三个方面对电推进系统在未来静止轨道平台上应用所涉及到的关键技术进行了分类及梳理：一是电推进系统与电推力器之间的关系,包括电推力器与推进剂贮存和供给子系统、电源子系统、控制子系统联合工作所涉及到的关键技术;二是电推进系统与化学推进系统的协调工作,包括两种推进系统的任务分工及相互影响所涉及到的关键技术;三是电推进系统对整星及大系统的影响,包括电推进系统对电源、热控、羽流污染控制、电磁兼容性（EMC）、遥测遥控、自主管理等所涉及到的关键技术。通过对这三个方面的关键技术进行梳理,明确了电推进系统在整星上应用所需要开展的工作。     

卫星编队飞行动力学仿真及其应用

由若干颗小卫星编队飞行组成一个虚拟卫星,其功能相当或超过一颗大卫星.这将开拓小卫星一个完全崭新的应用领域.文章首先论述编队飞行概念和应用,其次研究轨道动力学.系统地研究编队飞行三种动力学模型,最后进行电子侦察卫星和区域导航系统两个型号数学仿真,分析研究各种数学模型的精度和它们的应用场合.     

动态系统的纵向平滑器及其在GPS数据处理中的应用

许多诸如组合导航等动态系统大都存在冗余的观测信息，本文将带有冗余信息的动态系统的参数估计看成是纵向平滑问题。首先介绍了纵向平滑器的基本形式及推算公式，以ＧＰＳ动态定位为例，分析了纵向平滑器的特性。纵向平滑器在多传感器的导航信息处理、系统可靠性分析、粗差剔除等方面具有广泛的应用前景     

利用分布式卫星系统的轨道动力学和微推进技术实现的孔径全盛——TechSat21卫星的具体应用

利用分布式卫星系统实现的孔径合成为设计推进机动算法和分布式卫星系统的轨道构型开辟了新的研究课题。本文讨论了利用置于不同轨道高度（从近地轨道LEO到地球同步轨道GEO）的天基雷达系统实现合成孔径的运动目标识别和成像系统的设计问题。重点介绍空军TechSat21卫星计划的具体应用问题,给出了轨道摄动的定量表达式,为确定△V要求和任务寿命提供了依据。讨论了一维分布式孔径的角响应特性和等效二维分布式孔径的点散布函数,作为对比编队飞行卫星阵列性能的正确度量指标。文中按推进剂消耗量很多到最少的次序讨论了以较代的推进剂消耗实现最优阵列几可构型编队飞行的几种方法。针对这几种方法计算了所需的△V,并根据推进剂消耗量,估计了卫星的在轨飞行寿命。研究结果表明,所需推进剂消耗大大超过简单位置保持所需推进剂量的编队飞行策略对于本系统是不可行的,而对于所建设的系统,则要求采用比冲为500s的推进系统,以提供每圈轨道1cm/s的速度增量△V。     

Automatic calculation for bending of rigid-plastic beams under dynamic loading

Rigid-plastic stepped beams under impulsive or dynamic pressure loading are considered. The ends of the beam are simply supported, clamped or free. Permanent deflections of the beam are found by the method of mode form motions. For automatic calculation of the deflections a FORTRAN packet of programs DINOPT is put together. Three examples which demonstrate the facilities of this packet are given.     

磁悬浮轨道长波不平顺测试数据的预处理及时域分析

在进行数字信号分析中,首先必须要对信号进行预处理.这样一方面是对该信号的特性作判定,以便采用何种方法来进行处理,因为工程项目中的信号其不确定性因素很多,所采用的方法也不同,这应该是对信号定性的工作;同时做预处理也是对信号中一些由于机器、人为操作造成的异常数据的剔除,这可以归结为对信号定量的工作.根据对磁悬浮轨道长波不平顺测试数据的预处理,从而判定其为非平稳随机数据,针对该种数据的特性,采用现代信号时频分析的方法对其作进一步分析.     

Fast emergency control strategy calculation based on dynamic equivalence and integral sensitivity

Frontiers of Information Technology & Electronic Engineering - To simplify the transient stability analysis of a large-scale power system and realize real-time emergency control, a fast...     

Increasing mapping based hidden Markov model for dynamic process monitoring and diagnosis

Hidden Markov models (HMMs) perform parameter estimation based on the forward–backward (FB) procedure and the Baum–Welch (BW) algorithm. The two algorithms together may increase the computational complexity and the difficulty to understand the algorithm structure of HMMs clearly. In this study, an increasing mapping based hidden Markov model (IMHMM) is proposed. Between the observation sequence and possible state sequence an increasing mapping is established. The re-estimation formulas for the model parameters are derived straightforwardly based on these mappings instead of FB variables. The IMHMM has simpler algorithm structure and lower storage requirement than the HMM. Based on IMHMM, an expandable process monitoring and fault diagnosis framework for large-scale dynamical process is developed. To characterize the dynamic process, a novel index considering serial correlation is used to evaluate process state. The presented methodology is carried out in Tennessee Eastman process (TEP). The results show improvement over HMM in terms of memory complexity and training time of the model. Also, the power of IMHMM can be observed compared with principal component analysis (PCA) based methods.     

Finite elements and convergence for dynamic analysis of beams

Two different methods are considered for improving the accuracy of finite elements for calculation of dynamic response of the Bernoulli-Euler beam. One method involves a generalized-coordinate procedure in which quadratic displacement functions are used to formulate a non-consistent mass matrix. In the second approach, a lumped parameter model is developed by making the dynamic stiffness, or mechanical impedance, accurate at the connection points. The two finite elements developed are compared with the consistent mass model and a center-of-gravity lumped mass model. Of particular interest is the rate of convergence of natural frequencies and dynamic stiffness.     

Real time monitoring system for track chamber measurements

A system for monitoring track chamber measurements by using an on-line computer has been developed and realized in Pisa.

The system consists of

1. 1)
   np to seven measuring machines (MM), each provided with a console for displaying messages from the computer.     
   
   

Optimization and sensitivity of prestressed concrete beams

This paper is concerned with the optimum design of prestressed concrete beams. Both minimum weight and minimum cost optimization formulations are given for simply supported beams having three different sections. Sensitivity of the optimum designs, with respect to various design parameters, are also discussed. The formulation is programmed for interactive use on micro-computers. An example is given and results are discussed.     

High dynamic adaptive mobility network model and performance analysis

Since mobile networks are not currently deployed on a large scale, research in this area is mostly by simulation. Among other simulation parameters, the mobility model plays a very important role in determining the protocol performance in MANET. Based on random direction mobility model, a high dynamic adaptive mobility network model is proposed in the paper. The algorithms and modeling are mainly studied and explained in detail. The technique keystone is that normal distribution is combined with uniform distribution and inertial feedback control is combined with kinematics, through the adaptive control on nodes speed and prediction tracking on nodes routes, an adaptive model is designed, which can be used in simulations to produce realistic and dynamic network scenarios. It is the adaptability that nodes mobile parameters can be adjusted randomly in threedimensional space. As a whole, colony mobility can show some rules. Such random movement processes as varied speed and dwells are simulated realistically. Such problems as sharp turns and urgent stops are smoothed well. The model can be adapted to not only common dynamic scenarios, but also high dynamic scenarios. Finally, the mobility model performance is analyzed and validated based on random dynamic scenarios simulations.     

基于Vxworks的磁悬浮列车悬浮监控系统设计

磁悬浮列车的悬浮控制系统由各悬浮设备和相关控制仪器组成,控制仪器通过对采集到的设备信号进行分析和判断,实时调整信号量以实现列车在各工况下的稳定悬浮。本文基于Vxworks操作系统的网络通讯功能,采用Tornado和VC++编程工具,设计和实现了一个以太网通信系统,通过个人计算机对嵌入式控制器进行操作,如实时监控、参数调整、硬件故障判断等。