95 resultados para Clock Synchronization
Resumo:
对当前移动机器人上常用的激光测距仪的性能研究进行了全面的总结。分析了检测SICK、Perceptron、Explorer等常用激光测距仪各方面特性的各种实验结果。根据影响激光测距仪测量性能的方式,把激光测距仪的时变特性、角度偏移、数据传输影响、混合象素现象、色度亮度干扰现象、辐射干扰现象等,分为内因和外因两大类进行了分类讨论。
Resumo:
从系统组成、功能需求和体系结构方面介绍了航天器空间对接仿真系统的实时多任务控制系统,基于有限状态机和Petri网方法对其进行了单任务级和多任务级的分析建模,并以此为基础完成系统的详细设计,其中应用分叉和资源共享模型实现了系统的同步和互斥问题。实际应用中应用工程化和模块化的方法完成系统设计,系统运行性能良好。试验证明这种分析设计方法合理可行。
Resumo:
基于Internet的机器人遥操作系统提供了进行网络控制系统(NCS和多媒体通信等学科交叉领域研究的良好平台和契机。服务质量(QoS)的概念起源于多媒体和远程通信领域,大量的文献表明,将NCS和QOS结合起来的研究和应用还很少。本文分析、研究了基于Internet的机器人遥操作系统作为NCS, Internet上的多媒体应用和实时系统等多学科的交叉领域所具有的特点,对该系统同步和协调问题及具有QOS意识的网络机器人遥操作系统体系结构进行了深入、广泛的研究和探讨。就现有的基于Internet的机器人遥操作系统存在的缺乏对网络可用带宽的适应、缺乏多数据流协调等问题,提出了一种针对网络机器人遥操作系统的端到端QOS自适应体系结构AeQTA o在Internet QoS整体工程尚未完全启动的情况下,AeQTA的目的是将QOS的方法和策略尽量移植到端系统上,在端系统上提供QOS配置接口,实施QOS驱动的控制和管理策略,实现最大的网络效率、最可能好的应用性能和合理的业务流间资源分配的和谐统一。从时钟同步、速率控制、拥塞控制、多传感器信息同步和端到端的调度等几个方面剖析了基于Internet的机器人遥操作系统的协调和同步问题。针对NC S系统的同步容限的量化问题,提出了NCS多传感器反馈中的同步距离的概念和定义。然后,根据基于公式的、TCP-友好的速率控制的基本思路,结合使用应用需求QOS和网络QOS两种尺度调节的基于主媒体流的表象同步方法,将多传感器信息同步和速率控制统一起来,提出了一种速率控制方法TTFRC,提高了系统的实时性和TCP-友好性。为了给基于Internet的机器人遥操作系统研究提供一个真实的实验环境,为相关的策略和算法提供验证平台,我们建立了一个开放的、灵活的、可移植的、可裁减的且成本低的MOMR原型系统。目前,该原型系统已经为基于Internet的机器人遥操作系统深入的理论研究和实际经验积累做出了很大贡献。并且,在此基础上,由中国科学院沈阳自动化研究所和香港中文大学合作,己于2402年1月通过Internet实现了沈阳—香港—密西根三地的MONM远程协作。力求控制工程和计算机网络工程等多学科的结合是本论文工作的努力方向。
Resumo:
文中重点讨论了系统实现过程中,任务分解与行走命令下达,时序分配与同步,路标定位与行走误差修正.动态障碍感知,测定与响应和特别情况紧急处理等难题的解决策略及遇到的问题.
Resumo:
This project was carried out with the aims to investigate the mechanism of circadian immune regulation by one of the core Clock gene, mPer2. To achieve this, we selected mPer2 knock out (mPer2-/-) mice as the optimal animal model. Two different approaches were performed. In the first approach, we injected WT or mPer2-/- mice with an equal dosage of lipopolysaccharide (LPS), and systematically measured serum corticosterone induction, expression of core Clock genes, as well as a key enzyme for corticosterone metabolism (mStAR) in adrenal gland. We found that the acute induction of corticosterone and mStAR were closely associated with the circadian immune response to LPS. Besides, real time quantitative PCR (q-PCR) and luciferase assay consistently showed that mStAR is a Clock controlled gene in adrenal gland, where its expression is negatively influenced by mPer2. In the second approach, expression level and circadian manner of 11 cytotoxicity regulation genes in WT or mPer2-/- mice bone marrow were measured by q-PCR in order to explore the candidate genes which could mediate the circadian immune regulation by mPer2. We found that expression level of Ly49C, Ly49I, and Nkg2d was significant down-regulated in mPer2-/- mice. Further, we found that daily expression of Ly49C and Nkg2d fluctuated in a circadian manner in WT mice, where these rhythms were disrupted in mPer2-/- mice. Thus, it was suggested that these two cytotoxic genes were two clock controlled genes whose circadian expression were regulated by mPer2. Taken together, our results suggested that corticosterone, mStAR, Ly49C, and Nkg2d were four candidate molecules that may mediate the circadian immune response regulation by mPer2.