Modelling for an expert system and a parameter validation method

A model–based engineering diagnostic method is typically based on the evaluation of the residuals generated from a comparison of important variable values from a simulated system and the corresponding measured values from the system's performance. Consequently, a model should describe the dynamic behaviour of the system as accurately as possible using suitably selected parameter values. This implies the need for validation of the performance of the model by comparison with the measurements of the actual system. This process is especially important when the detection of faults is performed in real–time conditions. In this paper, the modelling process for hydraulic systems as well as a new parameter validation method that has been developed using the DASYLab data acquisition and control software for the estimation of the uncertain parameter values of the model is presented. This model validation process led to the establishment of a model–based expert system that is able to diagnose real–time faults working in parallel with actual dynamic industrial automated processes.     

Condition monitoring of CNC machining using adaptive control

In this work, an adaptive control constraint system has been developed for computer numerical control (CNC) turning based on the feedback control and adaptive control/self-tuning control. In an adaptive controlled system, the signals from the online measurement have to be processed and fed back to the machine tool controller to adjust the cutting parameters so that the machining can be stopped once a certain threshold is crossed. The main focus of the present work is to develop a reliable adaptive control system, and the objective of the control system is to control the cutting parameters and maintain the displacement and tool flank wear under constraint valves for a particular workpiece and tool combination as per ISO standard. Using Matlab Simulink, the digital adaption of the cutting parameters for experiment has confirmed the efficiency of the adaptively controlled condition monitoring system, which is reflected in different machining processes at varying machining conditions. This work describes the state of the art of the adaptive control constraint (ACC) machining systems for turning. AISI4140 steel of 150 BHN hardness is used as the workpiece material, and carbide inserts are used as cutting tool material throughout the experiment. With the developed approach, it is possible to predict the tool condition pretty accurately, if the feed and surface roughness are measured at identical conditions. As part of the present research work, the relationship between displacement due to vibration, cutting force, flank wear, and surface roughness has been examined.     

Supervisory fault tolerant control for a class of uncertain nonlinear systems

This paper focuses on the design of a unique scheme that simultaneously performs fault isolation and fault tolerant control for a class of uncertain nonlinear systems with faults ranging over a finite cover. The proposed framework relies on a supervisory switching among a family of pre-computed candidate controllers without any additional model or filter. The states are ensured to be bounded during the switching delay, which ends when the correct stabilizing controller has been selected. Simulation results about a flexible joint robotic example illustrate the efficiency of the proposed method.     

Fault tolerant control of a simulated hydroelectric system

This paper analyses the application of two fault tolerant control schemes to a hydroelectric model developed in the Matlab and Simulink environments. The proposed fault tolerant controllers are exploited for regulating the speed of the Francis turbine included in the hydraulic system. The nonlinear behaviour of the hydraulic turbine and the inelastic water hammer effects are taken into account in order to develop a high-fidelity simulator of this dynamic plant. The first fault tolerant control solution relies on an adaptive control design, which exploits the recursive identification of a linear parametric time-varying model of the monitored system. The second scheme proposed uses the identification of a fuzzy model that is exploited for the reconstruction of the fault affecting the system under diagnosis. In this way, the fault estimation and its accommodation is possible. Note that these strategies, which are both based on identification approaches, are suggested for enhancing the application of the suggested fault tolerant control methodologies. These characteristics of the study represent key issues when on-line implementations are considered for a viable application of the proposed fault tolerant control schemes. The faults considered in this paper affect the electric servomotor used as a governor, the hydraulic turbine speed sensor, and the hydraulic turbine system, and are imposed both separately and simultaneously. Moreover, the complete drop of the rotational speed sensor is also analysed. Monte-Carlo simulations are also used for analysing the most important issues of the proposed schemes in the presence of parameter variations. Moreover, the performances achieved by means of the proposed solutions are compared to those of a standard PID controller already developed for the considered model. Finally, these strategies serve to highlight the potential application of the proposed control strategies to real hydraulic systems.     

AIRBUS state of the art and practices on FDI and FTC in flight control system

This paper deals with industrial practices and strategies for Fault Tolerant Control (FTC) and Fault Detection and Isolation (FDI) in civil aircraft by focusing mainly on a typical Airbus Electrical Flight Control System (EFCS). This system is designed to meet very stringent requirements in terms of safety, availability and reliability that characterized the system dependability. Fault tolerance is designed into the system by the use of stringent processes and rules, which are summarized in the paper. The strategy for monitoring (fault detection) of the system components, as a part of the design for fault tolerance, is also described in this paper. Real application examples and implementation methodology are outlined. Finally, future trends and challenges are presented.This paper is a full version of the invited plenary talk presented by the author on the 1st July 2009 at the 7th IFAC Symposium Safeprocess '09, Barcelona.     

感应淬火综合监控系统设计

感应淬火综合监控系统集成了感应淬火能量监控与环境监控功能,其硬件基础为工控机与Y5000+多功能板,工控机通过并行口与Y5000+多功能板实现数据交换。Y5000+多功能板以CPLD芯片为核心,扩展了DI/DO、PI/PO以及AI/AO功能。感应淬火综合监控系统的应用程序分为上层管理程序与底层实时测控程序。在RTX支持下,系统完全能满足实时性与可靠性要求。     

高压氧舱自动监控系统的设计与开发

在高压氧舱自动监控系统设计中采用基于PC总线的工控机，利用PCL系列控制板对舱室进行控制，并利用Lab Windows／CVI虚拟仪器编程语言实现了监控系统的软件编程。采取了模糊-神经元控制策略，提高了系统的可靠性。     

MCGS在废水处理远程监控系统中的应用

以某电镀厂实际运行的废水处理系统为背景,应用MCGS和VB开发出远程监控系统,实现了远程数据显示、报警、报表、数据备份及恢复等功能,并对监控系统在扩展时可能遇到的问题进行了讨论。     

基于6LoWPAN的煤矿安全监控系统研究

针对传统的煤矿安全监控系统存在对监控主站的依赖性过高、无线覆盖范围窄、传感器部署不便等问题,设计了一种基于6LoWPAN的煤矿安全监控系统;给出了系统总体架构,详细介绍了系统的软件设计。温度数据采集测试结果表明,该系统工作稳定,采集与传输的温度值与实际温度相符。     

数据点表在远程监管系统中的应用研究

针对煤矿监测系统存在网络瓶颈、采集终端不兼容的现状,提出了一种基于数据点表的矿井瓦斯远程多级监控监管网络系统构架平台。该平台集成了远程监控系统的数据点表的结构、数据采集的文件格式、数据传输的数据格式、基础数据的生成和上传等核心技术。利用数据点表规定的标准接口消息方式实现系统远程监测和监控的数据传递及命令传达,使整个系统很好地解决了低投入与高效率之间的矛盾,具有远程监控、监管、维护、故障诊断和事故预警与决策功能。通过煤矿瓦斯监测监控工程实际应用说明,这种通信方式不受系统地理条件的限制,在数据传递过程中能够确     

基于RBF神经网络控制的球杆系统位置控制实验研究*

球杆系统是一种典型的高阶非线性不稳定系统,针对PID跟踪控制精度不高及BP神经网络控制训练时间较长的问题,本文提出一种带有低通滤波器的RBF神经网络控制器(RBFC)动态补偿PID控制的球杆控制方法,控制系统由RBF神经网络控制及PID控制器组成。为提高参数辨识速度和避免局部最小值,采用梯度下降法更新隐含层参数,采用带有遗忘因子的最小二乘法更新输出层权值。实验结果表明,该控制方案相比PID控制具有更高的控制精度,比BP神经网络具有更快的学习速度,低通滤波器保证了RBFC的辨识精度和稳定的控制输出,具有良好的动静态特性和控制性能。     

基于PC总线的推进剂加注自动监控系统设计

在火箭推进剂加注监控系统的设计中，采用基于PC总线的工控机，利用PCL和PCLD系列控制板卡对泵车与槽车进行控制，并利用VB实现了监控系统的软件编程。在软件和硬件上采取措施，提高了系统的可靠性。     

佛子岭水电站计算机监控系统的设计与应用

介绍了佛子岭水电站监控系统的系统结构功能及其特点,佛子岭水电站计算机监控系统满足了电站按"无人值班"(少人值守)模式运行管理的需要,实现了远方通信的功能。系统采用分层分布式设计,代表了国内水电站监控系统的主流设计趋势。并且在保证可靠性的前提下,充分满足水电站各方面信号实时性的要求。     

矿井通风除尘试验装置及PLC监控系统设计

基于实验室通风环境,设计了一套矿井通风除尘试验装置及PLC监控系统。该通风除尘试验装置集通风与除尘功能于一体,能自动监测通风机与除尘器的风量、风压、阻力等性能参数;PLC监控系统可对通风机、发尘器进行远程/就地开停及变频调速控制,实时监测通风机、发尘器运行状态、运行电流、运行频率等参数,模拟并实现了矿井通风系统的井下通风计算机远程集中监控。实际应用表明,该系统运行稳定可靠、操作简便、可扩展性强。     

一种新型煤矿安全监控系统信号转换器设计

针对目前煤矿安全监控系统主从应答式通信模式无法实现分站多主并发、实时通信及分站之间的联动联控等问题,提出了一种新型煤矿安全监控系统信号转换器的设计方案;给出了多环对等通信监控系统结构模型,详细介绍了信号转换器的软硬件设计。试验结果表明,通过信号转换器分站可以方便地实现多主并发及在线扩容,分站之间对等通信与控制无需上位机调度,有效缩短了危险区域的系统控制响应时间,提高了网络结构可靠性。     

基于DM365的井下多媒体监控系统设计

针对现有井下监控系统由于采用有线方式传输而存在布线难、网络覆盖不全及由于监控网络相互独立而造成成本高等问题,提出了一种基于DM365的井下多媒体监控系统的设计方案。该系统选用DM365视频处理芯片为硬件平台,嵌入式Linux操作系统为软件平台,集传感器无线数据传输和视频监控功能于一体,可对井下现场的视频、设备工作状况以及甲烷气体体积分数、湿度和温度等多维环境信息进行监测。实验结果表明,该系统提高了视频图像的处理能力,满足了井下无线传输距离的要求,适合在能量有限的煤矿井下使用。     

基于Petri网的煤矿斜巷监控系统研究

针对煤矿斜巷运输安全的实际,提出了一种基于PLC的集散控制系统,并利用Petri网对其进行建模。在建模过程中一方面采用了分层建模的技术,降低了模型的复杂性,并提高了系统的可靠性;另一方面,合理地采用了不同的控制方式,在充分保障系统安全性的前提下,尽可能地提高系统的实时性。此外,通过对Petri网模型的逐级分解、验证和优化,最终得到一个具备良构特性的Petri网模型。     

基于数传电台的无线远程监控系统设计

针对现有水源井供水、污水处理等监控系统采用有线通信方式存在投资成本高、通信距离长、数据传输速率低、传输量小等缺点,设计了一种基于数传电台的无线远程监控系统。该系统采用数传电台作为监控数据、视频和语音信号的传输介质,保证了数据传输的可靠性和实时性;采用组态软件作为远程监控软件,实现了系统的稳定运行。     

Adaptive output feedback control of general MIMO systems using multirate sampling and its application to a cart–crane system

In adaptive output feedback control based on almost strictly positive real conditions, a technical difficulty arises when the multi-input multi-output (MIMO) system under consideration is non-square, and in particular, has less inputs than outputs. To overcome this, we propose the idea of multirate sampled-data control—by carefully choosing faster input sampling rates, we obtain a lifted discrete-time system, which has the same number of inputs and outputs and does not give rise to the causality constraint. The adaptive control strategy is then applied to the lifted system, resulting in a multirate adaptive output feedback controller which is implementable digitally and provides closed-loop stability under certain conditions. The results reported here are validated on an experimental cart–crane system.     

煤矿监控系统双机热备数据同步软件设计

针对现有的煤矿监控系统双机热备方案存在存储设备投资费用高、可靠性相对较差、主机中断后恢复数据算法复杂等缺点,设计了基于纯软件模式的双机热备数据同步软件,该软件依据煤矿监控系统的实际应用情况,将监控数据同步功能从双机热备系统中独立出来,形成一个独立的软件,降低了双机热备同步算法和同步内容的复杂度,提高了双机热备的可靠性。