【作者】 张勇；

【导师】 徐久强；

【作者基本信息】 东北大学 ， 计算机应用技术， 2013， 硕士

【摘要】 信息物理融合系统(Cyber-Physical Systems, CPS)是综合了计算、通信和控制技术于一体的新型智能复杂系统。CPS深度融合了信息资源与物理资源,将再一次掀起信息产业的浪潮。它将深刻改变人类同信息世界和物理世界的交互方式。由于CPS深度融合、高复杂性以及信息量大等特点,其对网络QoS提出了更高要求,只有满足QoS要求才能保证系统的有效运行。本文首先分析整理了CPS的相关概念和研究现状,比较了CPS与相关技术的异同,重点讨论了CPS的时态特性及影响CPS网络性能的几种关键因素。在总结了CPS中各个控制回路的时态特性后,进一步分析了采样周期对系统的控制性能和网络性能的影响；在上述分析的基础上,提出了一种基于反馈调度的控制策略,设计网络反馈调度器,在线实时调整传感器的采样频率,以保证网络的稳定性。该反馈调度器包括等间隔采样网络带宽和错误传输率的网络QoS监测器、利用监测器获取的带宽值估计网络带宽调节量的QoS控制器和根据该调节量及获取的错误传输率调整网络参数的QoS执行器。QoS执行器计算出下一个任务周期的可利用网络带宽,并将带宽合理地分配给各个不同需求的控制回路,最终根据各个回路得到的带宽计算采样频率。其次,利用了PID控制和模糊PID控制,对反馈调度器中QoS控制器进行了详细的实现。分别介绍了PID控制和模糊PID控制的基本原理之后,在Matlab/Simulink工具箱下建立两种控制模型,最终完成对下一个任务周期网络带宽的可调节量的预测。最后,本文设计了一个信息物理融合系统的仿真实例。在该实例中,系统具有三个网络控制回路,它们共享有限的网络带宽。通过对比本文提出的反馈调度器与传统调度算法RM和EDF调度算法,说明本文提出的反馈调度器的可行性与优越性。更多还原

【Abstract】 As a kind of new intelligent complex system, Cyber Physical System(CPS) is the combination of the technologies of computing, communication and control. CPS is a deep integration of the information resources and the physical resources, it will follow the computer, the Internet, and once again set off a wave of the information industry. It will profoundly change the way which humans interact with the information world and the physical world. Because of its depth of integration, high complexity and large amount of information, etc., it must meet the requirement of OoS in network, in order to ensure the stability of the system. In the current research, the research for the QoS of CPS network is less.Firstly, we analyzed the related concepts and the research status about CPS, compared the differences between CPS and related technologies, discussed temporal characteristics of CPS and several key factors which influence the CPS network performance. After summarizing the temporal characteristics of each control loop, we further analysised the influence of sampling period on control performance of system and network performance. On the basis of above analysis, we proposed a scheduling strategy based on feedback scheduling, designed the network feedback scheduler, and real-time revise the sensor’s sampling frequency online, for ensuring the stability of the network. The feedback scheduler includes the network monitor, the controller and the actuator for QoS. The monitor samples the network bandwidth and the rate for error transmission in equal intervals. The controller uses the sample of bandwidth to estimate the amount of network bandwidth’s adjustment. The actuator calculates the available network bandwidth in the next cycle based on the adjustment amount and the rate for error transmission, thus allocates the bandwidth to each control loops which have different requirments, then calculates the sensor’s sampling frequency based on the allocated bandwidth, eventually maintains the system’s stability.Secondly, we propose a detailed implementation for the controller of QoS in the feedback scheduler with the utilization of the PID control and the fuzzy PID control. We introduce the PID control and the fuzzy PID control in the first, then we creat two control models in Matlab /Simulink toolbox, and complete the prediction of the bandwidth of the next cycle at last.Finally, this paper designs a simulation example for CPS. In this example, the system has three network control loops, they share the limited network bandwidth. By comparing the proposed feedback scheduler with the traditional scheduling algorithms-RM and EDF,it shows the proposed feedback scheduler’s feasibility and superiority.更多还原