无线网络控制系统的输出反馈控制器设计

鉴于无线网络控制系统在理论与实践两方面具有重要意义,考虑一类基于无线传感器网络实现的闭环网络控制系统,分析了无线传感器网络中采用的多跳通讯方式对网络延时的影响,提出了一种基于客户机一服务器模型的 LQR 输出反馈控制策略;利用线性矩阵不等式和切换控制系统理论,推导了系统的稳定性条件,给出了控制器的设计方法.实验结果表明了该算法的有效性.     

无线网络控制系统的最小延时路由协议设计

针对一类基于无线传感器网络实现的无线网络控制系统,分析了闭环控制系统中网络延时的组成,着眼于减少网络延时对控制系统性能的影响,从网络通讯的角度出发,提出了一种实现最小传输延时的路由协议算法,详细叙述了路由协议算法的设计和实现.在此基础上,对该路由协议算法的性能进行了验证,实验结果表明了该路由协议算法的有效性.     

Quantized stabilization of wireless networked control systems with packet losses

This paper considers stabilization of discrete-time linear systems, where wireless networks exist for transmitting the sensor and controller information. Based on Markov jump systems, we show that the coarsest quantizer that stabilizes the WNCS is logarithmic in the sense of mean square quadratic stability and the stabilization of this system can be transformed into the robust stabilization of an equivalent uncertain system. Moreover, a method of optimal quantizer/controller design in terms of linear matrix inequality is presented. Finally, a numerical example is provided to illustrate the effectiveness of the developed theoretical results.     

Novel delay-partitioning stabilization approach for networked control system via Wirtinger-based inequalities

This paper studies the problems of stability analysis and state feedback stabilization for networked control system. By developing a novel delay-partitioning approach, the information on both the range of network-induced delay and the maximum number of consecutive data packet dropouts can be taken into full consideration. Various augmented Lyapunov–Krasovskii functionals (LKFs) with triple-integral terms are constructed for the two delay subintervals. Moreover, the Wirtinger-based inequalities in combination with an improved reciprocal convexity are utilized to estimate the derivatives of LKFs more accurately. The proposed approaches have improved the stability conditions without increasing much computational complexity. Based on the obtained stability criterion, a stabilization controller design approach is also given. Finally, four numerical examples are presented to illustrate the effectiveness and outperformance of the proposed approaches.     

随机时延网络控制系统的优化控制

对具有不确定信息传输时延的网络控制系统的优化控制方法进行了研究。首先应用时间戳的BP神经网络对时延加以预测并建立了加热炉网络控制系统的数学模型。基于时间乘误差绝对值积分最小优化策略,给出了一次优化的设计方法,并导出相应的离散状态方程式。基于最优状态反馈提出的二次优化方法进一步提高了控制系统动态性能。最后的仿真和实验结果表明,提出的控制策略能有效地改善系统静态和动态特性。     

无线网络制造系统的信息安全研究

本文结合东南大学机电综合工程训练中心网络化制造系统,研究了该系统下的信息安全问题,并根据相关安全技术,提出了保障信息安全的措施,最后对其可行性做了相应的分析.     

网络化测控系统性能分析

网络化测控是自动测控领域的发展趋势.本文主要研究网络时间延迟的关键要素和采样时间间隔的最佳范围,为改善网络化测控系统的性能提供理论指导.     

Study of path loss and data transmission error of IEEE 802.15.4 compliant wireless sensors in small-scale manufacturing environments

Wireless sensors emerge as a promising candidate for supporting a wide range of plant floor monitoring applications in manufacturing; nevertheless, manufacturing environments are notoriously harsh for radio propagation. Usually abundant of stationary and moving objects, manufacturing environments may cause transmission errors among wireless sensors due to blocking, scattering, and multipath effects. This study aims to experimentally investigate the nature of such transmission errors due to common stationary and moving obstacles in small-scale manufacturing environments inside a machine shop and with a moving forklift, respectively. The measurement study was performed using the commonly adopted IEEE 802.15.4-based 2.4 GHz Zigbee radio. The measurements show that the occurrence of transmission errors closely depends on the received signal strength in both stationary and moving settings, and the transmission errors can be mostly avoided by controlling the transmit power to assure the received signal strength above the radio receiving sensitivity level. It is also found that electromagnetic noise due to the typical machinery has negligible effects on the transmission error.     

Performance limitations of networked control systems with quantization and packet dropouts

This paper investigates the problem of optimal tracking performance of networked control systems (NCSs) with quantization and packet-dropouts. The system under consideration is linear time-invariant (LTI), multi-input multi-output (MIMO), where an H₂ norm of error signal between the reference input and the system output is used as the tracking performance index. The impacts of packet-dropouts in the communication channel and the quantized input and output are studied. The goal is to obtain the minimal error in tracking a random signal, by searching through all possible stabilizing two-parameter controllers. It is shown that, the minimum value of tracking error is closely related to the reference input signal direction, the non-minimum phase zeros and unstable poles of the given plant, including the locations and directions. We also demonstrated the quantization error and the packet-dropouts may degrade the tracking performance. A typical example is given to evaluate the theoretical results.     

CAN总线的CSMA/CA通信过程的DSPN建模与性能分析

针对采用CSMA／CA协议的CAN总线通信过程进行建模及性能分析，应用确定与随机Petri网DSPN，对每个节点进行确切的描述，构成一个单网段复合模型，并在此基础上构建一个简化的紧缩模型。仿真实验验证了紧缩模型能够很好地逼近复合模型，且求解时间短，可以通过紧缩模型进行CAN总线系统吞吐量、平均信息时延、通信冲突率和网络利用率的定量和定性分析。     

Issues and mitigation of interference,attenuation and direction of arrival in IEEE 802.15.4/ZigBee to wireless sensors and networks based smart building

The performance metrics of IEEE 802.15.4 standard make it an only dominant option in short-range environmental monitoring and control applications. The heterogeneous sensor and actuator nodes based on the wireless technology are deployed into the smart building environment. Wireless technology deployed in building environment suffers from interference from different communication protocols operating in the same unlicensed ISM band, apart from the attenuation loss. A designer could not ignore these factors in the smart building because the adverse effect of these issues on system performance is considerable. Most of the researchers reported this but not with the aspects of the smart building. This research paper reports on the detailed experimental analysis and mitigation for different types of interference, the direction of arrival and attenuation losses associated with smart building condition. This research also tries to find the mitigation by direction of arrival of the radio signal. Our research aims to generate the customized methodology that will support and assist the smart building system designer to evaluate and measure the on-site performance so that these assessments will be precise, efficient and accurate. A realistic, smart home solution is applied to the building.     

网络化控制系统的协同设计与形式化建模

为满足网络化控制系统的综合性能要求,实现其设计过程的形式化和规范化,针对其设计过程进行了形式化建模。给出了网络化控制系统中网络、控制、结构实体三个子模型的定义,分析了三者的构成要素以及相互之间的映射关系;进而提出了基于网络服务质量和控制性能质量的协同设计框架,并利用统一建模语言进行网络化控制系统的结构实体子模型设计,分析了网络化控制系统建模中类的概念和构造,针对类的属性和方法进行了扩展,归纳了建模过程的一般性步骤。最后以一台网络化三轴数控钻床的设计过程为例,实现并验证了所提出协同设计框架与形式化建模过程的可行性。     

Performance evaluation of control chart for multiple assignable causes using genetic algorithm

With a view to monitoring and controlling manufacturing processes in industries, control charts are widely used and needed to be designed economically to achieve minimum quality costs. Many authors have studied the economic design of the $ \overline{X} $ control chart after Duncan (J Am Stat Assoc 51(274):228–242, 1956) first proposed the economic model of the $ \overline{X} $ control chart for a single assignable cause. But, in practice, multiple assignable causes are more logical and realistic. Moreover, the economic design does not consider statistical properties like bound on type I and type II error, and average time to signal (ATS). This paper focuses on evaluating the performance of genetic algorithm (GA) in pure economic and economic statistical design of the $ \overline{X} $ control chart for multiple assignable causes. The performances of GA are demonstrated by comparing its result with the previously proposed grid search technique for a numerical example. The Duncan model of multiple assignable causes is adopted to formulate objective function, and the computation is achieved by approximation through a numerical method named Simpson's 1/3 rule. Comparison distinctly shows the superiority of GA over grid search results for economic statistical design.     

无线Intranet的网络制造实验室DNC系统通信技术研究

介绍DNC系统通信的基本原理及网络结构,对网络DNC通信技术进行研究,并结合实际情况介绍了网络制造实验室的DNC系统的联网方案.最后对DNC系统应用中通信参数的设置及通信规范进行了阐述.     

基于工业以太网的网络数控系统设计及实现

在分析网络数控技术发展历史基础上,重点介绍工业以太网的网络数控系统硬件平台和软件平台的设计与实现,具有很强的实际应用性。     

基于执行器部分失效的网络化控制系统完整性研究

针对一类具有马尔可夫特性时延的网络化控制系统,考虑系统参数不确定性的影响,基于时延T-S模糊模型建立数学模型,通过构造离散Lyapunov函数,推证出了确保网络化控制系统在执行器部分失效时具有鲁棒完整性的充分条件,并以求解LMIs给出容错控制器的设计方法.最后通过仿真验证了文中所述方法的可行性和有效性.     

嵌入式以太网网络控制系统的实现

设计一种基于嵌入式以太网的网络控制系统.针对工业控制领域要求现场节点实现以太网功能,控制系统网络化的问题,给出一种应用于测控系统的基于嵌入式μC/OS-II的具体实现.该实现将嵌入式以太网作为监控端和现场测控单元的通信介质,解决了监视层和控制层的无缝连接问题.阐述了系统的结构和工作原理,系统的硬件电路和软件设计.系统调试结果表明,远程控制方案可行,有一定的应用价值.     

一种装载机的无线遥控系统设计

为了提高在不安全或环境恶劣的机车凋车作业现场的安全性、方便性及其作业效率,以厦工装载机为实验平台,开发设计一种应用于工业现场,具有远距离、高町靠性的多路无线遥控系统.该遥控系统由发射、接收和驱动控制三部分组成,提供无线键盘操作控制与PC机界面独立操作控制的两种遥控模式,同时,软件部分采用了模块化结构设计方法.经过多次现...     

一种工业无线遥控系统设计

应用MSP430f1232和NRF24L01集成电路设计了一种工业无线遥控系统。介绍了该系统的硬件组成结构和软件实现流程,给出了部分实现程序。经过试验表明,该遥控系统可通过手持端指示灯动态获取接收端工作状态,可以提高工业场合远距离作业时的安全性,适用于单钩、单速电动葫芦或葫芦式桥式起重机。系统结构简单,经过改进也可用于其他设备的控制。     

基于变采样周期的网络控制系统协同设计综述

大量的信息传输给有限带宽的网络控制系统设计带来了诸多挑战。针对网络控制系统的大规模及分布性,该文以采样周期为切入点概述了带宽受限情况下解决网络控制系统数据传输及控制系统设计的方法,并对基于变采样周期的网络控制系统控制与调度协同设计方法作了必要展望。