共查询到18条相似文献,搜索用时 137 毫秒
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介绍ZJ120DB钻机改造前存在的问题,改造方案,网络系统结构,双CPU冗余系统S7-400H的结构、原理、特点等。 相似文献
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针对航空电子产品高可靠性和可测试性要求,以某型起落架转弯操纵系统为对象,采用余度设计和机内测试(BIT,built-in-test)技术,开发了一款起落架转弯双余度控制器。该控制器基于三CPU冗余架构,采用相似余度、冷备份的双余度方案以及基于AT89S51单片机的BIT方案,实现工作电路板的故障检测、监控、诊断和隔离。通过基于硬件的故障注入技术对该控制器BIT功能验证,结果表明该控制器BIT检测模块能够检测到电路板故障,显示故障信息,并自动完成系统重构。同时,在软件方面采用数字滤波技术,进一步提高了BIT的可靠性,降低了虚警率,达到了预期的初步设计目标。 相似文献
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为了解决泥沙输送实验平台控制系统可靠性不高的问题,采用硬冗余技术,以西门子400H PLC为控制核心,分别在CPU、通信网络和上位机等方面进行了冗余设计,并进行了组态和编程实现,建立了具有冗余和容错功能的泥沙输送实验台控制系统。同时,通过USS通信协议,实现了315 k W西门子MIDIMASTER系列变频器的控制和参数采集,并利用Y-Link组件将其融入到冗余系统中,降低了大功率变频器对控制系统的干扰,丰富了采集参数。实验结果表明,冗余控制系统具有很高的容错性能,可以有效避免因宕机、通信中断或CPU报错等故障所造成的实验平台失控现象,从而大大提高了实验平台的控制可靠性。 相似文献
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冗余捷联惯组可以提高运载火箭导航制导系统的可靠性,针对五冗余捷联惯组设计其最优配置方案。方法是基于无故障时系统性能指标函数和发生故障时的导航性能指标函数,对五冗余系统的特殊形态(三正交两斜置结构)进行分析,得到五冗余捷联惯组的最优配置;进一步研究故障发生时对单故障正交轴的重构方法。仿真实例表明,配置方案和重构技术有效,为运载火箭导航制导系统设计提供一种设计思路。 相似文献
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小型D系列风机属于旋转机械,要求控制系统具有较高可靠性。西门子S7-400H硬冗余系统的价格较高,而S7-300单站控制系统的安全性级别又无法满足部分实际应用需求。具有高性价比的S7-300软冗余控制方案则平衡了价格与可靠性之间的矛盾。该文详细分析了西门子公司的软冗余软件包,得出了软冗余的基本原理;并通过软件编程实现了WinCC flexible和主备CPU的冗余连接切换。该方案已应用于某D1500煤气离心压缩机控制实例中,系统的可靠性满足风机安全运行的要求。 相似文献
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冗余功能是一个工业控制网络系统成功的关键环节,是保证系统稳定、安全、可靠的重要手段。文章在西门子S7-300软冗余系统工作原理的基础上,提出了软冗余系统的硬件组成及程序实现方法,通过电源模块、CPU、冗余模块、通信模块以及I/O等相关硬件,完成相应的软件组态。 相似文献
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针对具有参数不确定性和传感器故障的非线性机电系统,提出一种基于优化自适应阈值和故障重构策略的主动容错控制方法。首先,利用线性分式变换理论对存在参数不确定性的非线性机电系统进行建模,并提出基于粒子群优化算法的优化自适应阈值以提高参数不确定条件下的故障检测性能。其次,通过解析冗余关系推导出系统的动力学方程,并提出一种基于递归终端滑模的跟踪控制策略,以实现系统健康状态下的负载位置跟踪。当系统发生故障时,构建自适应滑模观测器进行传感器故障重构,根据重构结果设计自适应主动容错控制律,并利用故障检测结果进行控制律的实时切换。实验结果表明,所提出的故障检测和主动容错控制方法能在0.06 s内准确的实现传感器故障检测和容错控制,验证了该方法的可行性。 相似文献
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Kenneth Anderson 《ISA transactions》1991,30(4):107-116
Although most control project specifications for modern digital systems include references to redundancy and fault tolerance, little effort usually is expended to analyze the cost additions to the project. Risk assessment applied to a control system most often maximizes reliability without regard to cost, though the additional expense may have no significant justification. On some projects, redundancy is carried to extremes, while other times partial redundancy is added with minimal gain in overall system reliability.
This paper will assist the project engineer in properly analyzing the benefits of redundancy versus the true cost of this capability and the effect this will have on a project. The methodology described attempts to achieve the system's objectives and quantity the requirements that will be placed on system reliability. The emphasis is not on the cost or safety benefits to the process but on the relative cost/benefits associated with different offerings that implement fault tolerant or redundant functions. 相似文献
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无线闭塞中心(RBC)系统是CTCS-3级列控系统的核心设备,在现场其故障分析主要依靠人工完成,诊断结果不精确、效率低。因此,提出了基于one-hot模型、核主元分析(KPCA)和自组织映射(SOM)网络的RBC系统智能故障诊断方法。首先,通过人工选取的故障特征词库和故障追踪记录表构建基于“one-hot”模型的故障文档矩阵;其次,利用核主元分析方法对故障文档矩阵进行降维降噪处理,避免信息冗余;最后将处理后的数据输入至SOM网络,训练生成KPCA-SOM故障分类模型。通过与BP神经网络算法、SOM网络算法比对分析,KPCA-SOM智能诊断方法可有效地对列控RBC系统常见故障类型进行区分,并且在准确率和处理效率上进一步优化提升。 相似文献
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《Measurement》2016
In this work, we present the design of a Fault-Tolerant Control (FTC) system, applied in the outlet temperature sensors and in the control valve (actuator) of a concentric double pipe counter-current flow heat exchanger. The FTC consists in a sensors Fault Detection and Isolation (FDI) system and an actuator FDI system. The sensors FDI system is based on analytical redundancy, in such a way that a bank of modified Kalman filters is developed in order to estimate the two outlet temperatures of the heat exchanger. To develop the modified Kalman filters a multi-linear models approach is used. So that, if a sensor fault is detected by the FDI system the measured temperature signal is replaced by the temperature estimation provided by the modified Kalman filter. Moreover, to detect an actuator fault a comparison between the control valve behaviors (the control valve voltage is used to estimate the water flow rate) and a predefined flow rate for each linear model is carried out. In order to keep the continuous operation of the heat exchanger even in fault presence a model-following control law is introduced, such that, when an actuator fault occurs, the FDI system detect the fault and immediately the model-following control makes the fault accommodation in order to compensate the actuator fault. The proposed scheme is presented with experimental data on-line. The successful tests are presented and discussed. 相似文献
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The design aspects of the implementation of a fault tolerant distributed control sytem are reviewed, including specific strategies for processor and input/output redundancy. Actual results of component and system reliability achieved through the fault tolerant design are discussed as well as the implications of these results for the user. 相似文献
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根据伺服系统安全设计和LVDT冗余设计原则提出了双通道低选位置反馈方式和提高伺服机构可靠性的冗余设计方案,大大减小因阀位反馈信号故障而使伺服机构误动作的可能性,从而提高伺服机构动作的可靠性. 相似文献