基于OSG的空间机械臂三维仿真平台的设计与实现

为了实现空间机械臂路径规划算法的可视化仿真,采用OSG技术,开发了一个实用方便的空间机械臂三维仿真平台;该仿真平台在VS2005开发平台上,基于QT框架类和OSG的图形库进行开发,将仿真平台系统框架分为了OSG仿真界面,任务管理,数据管理和路径规划四个模块并设计了人机交互界面;最后,通过典型的仿真实验对仿真平台进行了测试,有效地验证了空间机械臂单臂路径规划算法和双臂协调路径规划算法的正确性以及空间机械臂三维仿真平台的可行性。     

串口数据丢帧引起的雷达测试故障原因分析

为解决某雷达高度表试验过程中发生的动作高度测试异常故障,采用故障树分析法对雷达高度表和测试设备进行故障排查。经检测发现,测试设备上位机的串口通信卡接收下位机的数据中有几十帧数据帧出现CRC校验位错误,被应用程序丢弃。原因是下位机发出的数据信号存在一定程度的畸变,上位机串口通信卡的串口控制器芯片OX16PCI694适应性不足导致数据读取出错。而应用程序在健壮性设计上也存在缺陷,以数据帧数来计算时间及雷达动作高度,但丢弃数据帧时未作相应处理。采用兼容性好的串口控制器芯片16C554重新设计通信卡,在上位机与下位机通信协议中增加数据的帧序号。经试验验证故障定位正确,解决措施有效。     

Dynamic isotropic design of a class of Gough-Stewart parallel manipulators lying on a circular hyperboloid of one sheet

This paper proposes an optimal design method based on dynamic isotropy conditions of a generalized natural frequency matrix in task space for a standard Gough-Stewart parallel manipulator (GSPM). Firstly, the dynamic isotropy conditions are discussed and presented. Next, it is proved that standard GSPMs lie on a circular hyperboloid of one sheet. Further, we present a method to use a circular hyperboloid to construct 3-3-, 6-3- and 6-6-type standard GSPMs. Moreover, such novel definition is used to examine various dynamic isotropy conditions as functions of the coefficients of a hyperboloid. An optimal design method is also proposed accordingly. Finally, a numerical example is given to illustrate the design procedures. The results are very close to the complete dynamic isotropy.     

Towards ETEM serial crystallography: Electron diffraction from liquid jets

A sufficiently thin column of liquid was produced to permit penetration with a 200 keV electron beam as evidenced by the observation of diffraction rings due to the intermolecular spacing of the liquid samples. For liquid thickness below 800 nm, the diffraction rings became visible above the inelastic background. Studies were carried out in the environmental chamber of a transmission electron microscope using water and isopropanol.     

基于双目视觉的机器人目标定位与机械臂控制

为了更好地与复杂多变的非结构化环境进行交互,完成对目标物体的识别和抓取,提出了一种应用于服务机器人平台的基于双目视觉的仿人机械臂控制方法.文中首先用D-H方法对机械臂进行建模,并对这个模型做了改进,给出了一种更加简便的3+1自由度仿人机械臂的逆解算法,采用基于双目视觉与颜色分割的目标识别方法;然后根据识别出的目标三维坐标信息控制机械臂完成抓取任务;最后,本方法在家庭服务机器人上得到了验证,机器人能够完成对目标物体的识别和抓取动作.     

贝叶斯网络在空间机械臂故障诊断中的应用研究

空间机械臂在空间设施中广泛应用,如何准确快速判断其运行状态成为需要解决的重要问题。文中首先介绍了机械臂在国内外空间设施的应用背景,然后采用基于故障树与贝叶斯网络的故障诊断方法,包括：基于系统组成结构的故障树建模、贝叶斯网络转化、团树传播算法和最大后验估计(MAP)推理结果分析。最后利用单点故障实验和多点故障实验对所提方法进行了验证,结果表明将故障树分析和贝叶斯网络结合应用到空间机械臂故障诊断是有效的、可行的。     

Robust Saturated PI Joint Velocity Control for Robot Manipulators

It is well known that many industrial manipulators use an embedded linear proportional‐integral (PI) joint velocity controller to guarantee motion control through proper velocity commands. However, although this control scheme has been very successful in practice, not much attention has been paid to designing new PI velocity control structures. The problem of analyzing a saturated PI velocity joint velocity controller is addressed in this paper. By using the theory of singularly perturbed systems, the closed‐loop system is studied. The robot dynamics assumed in this paper take into account bounded time–varying disturbances which may include the friction at the joints. An experimental study in a planar two degrees‐of‐freedom direct‐drive robot is also presented, confirming the advantage of the new saturated PI joint velocity controller.     

基于T89C51AC2多点温度检测系统的设计

系统采用主从式结构,采用T89C51AC2作为控制元件.在从站电路中,根据PT100铂电阻的温度特性,设计测温电桥,输出电压变量,并将此变量由测温点,经过集成运放TL064组成的精密放大电路放大输出,经A/D转换送至从控制器.从控制器处理转换并显示当前测控点的温度,通过RS485总线将温度值传送到主站.主站采用轮询的方...     

基于ARM系统的多路气象数据串行通信设计

本文针对外场观测中多路气象数据传输和存储的要求,在一款以ARM9 S3C2440为核心处理器的开发平台上,重点对串行通信接口进行了设计。文章阐述了多路气象数据串行通信的研究背景和意义,搭建了基于ARM S3C2440处理器的硬件平台和基于Linux系统的开发环境,并在Linux下建立了针对ARM板的交叉编译环境,编写了串口通信的应用程序并对其结构进行了分析。     

基于PDA的肉牛养殖可追溯系统的设计与实现

为提高肉牛养殖信息采集、传输的效率和准确性,本文通过对肉牛养殖企业的实地调研,在分析肉牛养殖流程的基础上,对肉牛养殖环节质量安全的关键信息进行了分析,并设计了基于PDA肉牛养殖质量安全可追溯系统的整体结构和功能模块,重点分析了该系统的实现技术。该系统改变了肉牛养殖纸质、人工的信息采集方式,实现了养殖场信息的快速、高效、准确的采集与传输。