Periodical Motion of a Tethered Satellite System around Collinear Libration Points

This paper studies the motion of a rotational tethered satellite system flying around collinear Lagrangian points of the Earth-Moon system. Equations of spatial motion of the mass center and the tether libration are deduced, but only the planar motion with constant rotation rate is discussed. First, the equation of the mass center is simplified and solved analytically for the scenario where the system is moving in the neighborhood of the libration point. The analytical solution indicates that both a bounded solution and periodical solution exist. A fully nonlinear dynamics analysis is then performed. A numerical method combining continuation and piecewise differential corrections is applied to obtain the periodical solution. Tether tension is also investigated. Simulation results validate the effectiveness of the proposed numerical method and the existence of the periodical orbits. The influence of parameters, such as spin rate, mass ratio of end satellites, and tether length are analyzed.     

基于ControlLogix平台的备煤控制系统

针对煤场地域广、设备分布线长等特点，备煤控制系统采用了两套大型的ControlLogix控制器，分别对输送工段、粉碎与除尘工段加以控制，而煤塔工段因控制点相对较少，采用微型的SLC5／04控制器。三套控制器之间利用ControlNet和DH 构成通讯网络，各监控站通过RSlinx与PLC通讯，以完成致据的实时采集与控制。系统投运后，自动化控制水平大幅提高，网络的应用使控制更加方便快捷、维护简单；备煤生产能力也由原来的日产3000t上升至近7000t。     

基于OPC技术搭建的工控信息平台

针对当前白银有色集团铜业公司过程控制现状,应用OPC技术实现全厂搭建工控信息平台,将目前在用的不同厂家、不同系统、不同品牌的各分散的控制系统的数据集中显示、远程管理,实现全厂工业监控数据资源共享。     

FPGA Based Satellite Adaptive Image Compression System

Space-borne imaging sensors onboard remote sensing satellites capture images of specific interest to the mission. These images contain tremendous volumes of data. Storage capacity onboard the satellite is limited and downlink channels have limited bandwidth capacity. Moreover, most remote sensing satellites are visible to their ground stations for only short periods of time during the day. Therefore, there is significant delay between image capture and terrestrial analysis. Hence, onboard image compression is essential to deliver captured data to the ground in a timely fashion. Smart and efficient onboard image compression using reconfigurable computing technology such as field programmable gate arrays (FPGAs) represents a unique solution that significantly increases the mission effectiveness. The High Performance Computing (HPC-I) payload on the Australian scientific mission satellite FedSat is a demonstration of reconfigurable computing technology in space for a variety of applications including image compression. In this paper, we present the design and implementation on HPC-I of the Satellite Adaptive Image Compression System (SAICS) for space missions. The system concept is based on an FPGA implementation of the adaptive JPEG-LS algorithm. The SAICS is a low complexity, high speed adaptive compression system that uses lossless and near lossless techniques depending on local image statistics. Performance evaluation indicates that satisfactory compression results can only be achieved through a careful trade-off between design complexity and efficiency.     

基于三维地理信息系统的岩层产状测量方法

利用三维地理信息系统技术和多比例尺的国家基础地理信息数据,在计算机软硬件平台支持下,进行浅层岩层产状的测量和计算,可以用来替代传统的野外测量.该方法利用数字地面高程和高分辨率的数字正射影像图数据,建立研究区域的三维场景,在计算机辅助下实现动态实时测量各种浅层岩层产状.通过选取和测量岩层上10个以上点的三维空间坐标,并利用最小二乘法原理求解测量点所构成的拟合平面,根据拟合平面方程计算岩层产状的各个要素.该方法可通过专家可视化判别岩层产状计算的可靠性,并可通过不断修改测量点位置,经迭代计算提高岩层产状的准确性.     

基于挖掘机GNSS精确定位的开采姿态监测系统

通过对GNSS高精度定位、角度传感器工作原理的分析及液压挖掘机工作装置运动的研究,利用安装在挖掘机尾部GNSS天线,驾驶室顶部、斗杆以及动臂处的角度传感器,将GNSS高精度定位、车体姿态测定、运动学问题求解技术与算法写入到程序中,完成了整个挖掘机的精确定位和工作装置的姿态监测。系统基于挖掘机实时可靠的定位和工作姿态监控,结合矿体地质地理信息数字化,实现采矿引导,包括目标采场位置、铲斗位置、铲斗当前位置下方矿体信息以及采场边界等图形化显示。测试结果表明,挖掘机姿态监测精度高,基于挖掘机姿态监测的采矿引导系统具有较为广阔的应用前景。     

基于FIX平台的电力监控系统应用

济钢燃气蒸汽联合循环发电工程采用了基于FIX平台开发的电力监控系统Power SCADA,该系统具有数据采集、遥控操作、数据报表生成、趋势曲线显示、报警管理、系统安全管理、调度自动化等功能。系统应用后,满足了电网实时监控要求,上位机监控画面完备,报警功能齐全。     

双辊薄带铸轧机过程控制系统平台开发

针对双辊薄带铸轧机的过程控制要求,设计并开发了一个多进程形式的过程控制系统平台。该平台包含 多个进程,每个进程实现不同的功能,进程之间相对独立。这样的架构设计使平台具有良好的可伸缩性和稳定性。 在平台开发过程中,使用自适配通信环境ACE实现进程及线程间的通信,大大降低了开发难度,缩短了开发周期。 经过长时间测试,表明该系统平台运行稳定,能够满足在线控制要求。     

基于ERP平台的生产管理系统分析

以某公司ERP系统的生产管理子系统为研究对象,运用ERP系统的管理思想,对企业原有的生产管理系统进行了分析,找出了其中存在的主要问题;提出了构建基于ERP平台的生产管理系统的解决方案;并简要介绍了系统的实施效果。     

天铁财务成本管控系统硬件平台设计

为满足天铁财务成本管控系统应用业务和业务扩展的需要,对系统硬件平台的安全性、可靠性、性能等方面需求进行分析,采用成熟的技术和设备设计了硬件平台环境.该硬件平台的建立解决了原财务管理系统在运行中存在的问题,保证了系统的可靠性、稳定性及安全性,并对财务成本管控一体化的顺利实施和应用起到了重要作用.     

Next Generation Space Telescope. II: Proposed Pointing Control System

The pointing control system of the Hubble Space Telescope (HST) represents the current state of the art for the precision control of a large spacecraft. The proposed Next Generation Space Telescope (NGST) will require an order‐of‐magnitude increase in pointing resolution over that of HST. The use of active optics in the form of a steerable secondary mirror has been proposed for NGST to satisfy these requirements. The primary motivation for this study was to demonstrate the feasibility of satisfying the pointing‐stability requirements by sensing the guide‐star position and steering the optical path of the telescope with the active secondary mirror. To study the requirements of the control system, a two‐degree‐of‐freedom model that retains the rigid‐body mode of the telescope as well as its first oscillatory mode was constructed. The corresponding optimal control law was developed and implemented in a discrete manner to examine the behavior of the system subject to typical spacecraft excitations.     

基于多模型自适应控制方法的FGC控制

冷连轧机动态规格变换时各机架的入口厚度一般变化较大,采用传统自适应控制的辨识算法的收敛速度不能跟随参数实际变化速度,控制效果不佳.针对这一问题,提出一种多模型自适应控制方法.通过对五机架冷连轧机进行仿真表明,多模型自适应FGC系统具有较好的控制精度、跟踪速度以及稳定性.     

基于PLC的挤压机控制系统

阐述了挤压技术的应用现状,提出了挤压机控制系统的硬件组成方案和设计思路,分析了系统控制原理和控制算法,介绍了PLC的选型方法、端子分配表和端子接线图以及PLC控制程序流程图.     

基于模糊控制算法的炉温控制系统

在工业电炉的控制过程中,由于被控参数具有时变、非线性、不确定等因素,常规PID控制算法难以满足控制要求.可采用模糊PID算法实现对工业电炉的控制,利用模糊推理在线整定PID控制器的3个参数Kp、Ki、Kd.实际运行结果表明,该控制器取得了较好的快速性和稳定性.     

基于现场总线技术的转炉控制系统

在分析现场总线的基础上,论述了基于PROFIBUS现场总线技术的转炉监控网络的组网实例。该系统主要选用了Siemens公司的S7-400CPU作主站,WAGO公司的I/O远程系统作从站组网,实现系统控制。并借助WINCC组态软件对下位机的监控和控制,完成了对现场数据的实时采集和处理。     

基于AutoCAD的参数化破碎机CAD系统的开发

阐述了一个参数化破碎机ＣＡＤ系统的整体设计方案,并通过复摆颚式破碎机子模块和机械设计资料查询模块的具体介绍,说明了该系统的开发方法。     

基于矢量控制和智能控制的交流伺服控制系统

根据交流伺服电机数学模型和矢量控制理论以及模糊控制理论,实现了以DSP为控制器、IPM为主回路,以模糊控制器为速度环,以矢量控制滞环比较器为电流环的交流伺服系统.在此基础上,进行了模糊神经网络控制的仿真.通过仿真及实验结果,证明了该系统具有一定的理论意义和实用价值.     

Motion Control of Space Structures

A new area of civil engineering is emerging as we begin to establish a permanent presence in space. The new area of civil engineering is the motion control of space structures. This paper describes why the motion control of space structures is fundamentally a civil engineering problem.     

Model and Control of Flexible Multibody Satellite

In order to estimate total disturbances including parametric uncertainties, unmodeled dynamics, and external disturbances, and achieve the dynamic feedback compensation of the estimated total disturbances, we design a double closed loop attitude active disturbance rejection controller (ADRC). By taking flexible vibrations of solar panels and a flexible antenna as an external disturbance, and using only the estimated transformation matrix of control input, a simplified dynamic model has been used to replace the accurate dynamic model of a rigid body in a flexible multibody satellite dynamics model. Simulation results indicate that the attitude ADRC designed still has the original dynamic response when large external disturbance acts on the system. Therefore, we come to the conclusion that the ADRC designed can be used to solve the problem of control systems with uncertainties in the process of modeling different flexible multibody systems.     

基于机器视觉的对中控制系统

为了解决带材轧制过程中跑偏的问题,介绍了一种基于机器视觉的对中控制系统．及其原理和硬件、软件系统组成,并着重介绍了基于虚拟仪器开发平台Labview的图像处理模块.系统体积小,安装方便,两路数据可完全并行处理、用软件措施来替代以前惯用的硬件处理方法,硬件配置灵活、而且成本适中、精度高、响应速度快、机干扰能力强.