用控制系统提供的信息对空压机跳车故障分析与处理

以故障实例,应用DCS系统的记录、趋势、逻辑和励磁系统报警信息,对空分装置的空压机跳车进行分析,同时对控制系统的趋势功能有更进一步的了解和认识。     

An Efficient Expert System for Air Compressor Troubleshooting

In this paper, an expert system for automobile air compressor troubleshooting (ACTS) is presented. This system can assist users to conduct an efficient and effective diagnosis on air compressor failures. Unlike most diagnosis expert systems, ACTS uses a new control strategy to enhance the efficiency of the diagnostic process. This control strategy attempts to spend the least amount of time to detect the compressor fault accurately by investigating only portions of the knowledge base. ACTS first constructs a diagnostic tree based on the functions or connectivity of the air compressor's devices. A fuzzy multiple-attribute decision-making method is used to determine the priority of the nodes (devices) in the diagnostic tree. The prioritized result creates a 'meta knowledge base' to control the diagnostic process. In addition, each node possesses its own knowledge base for hypothesizing the possible faults for the node. ACTS, written in MS Visual BASIC, has been successfully developed and implemented in MS-Windows environment on a PC. To validate the system performance, ACTS is compared to EXACT, an expert system for automobile air compressor troubleshooting, using 50 sample cases. The evaluation results indicate that ACTS performs better than EXACT by reducing the number of queries and the diagnosis time by 20.7% and 24.9%, respectively.     

A Continuous Analysis Method for Planar Multibody Systems with Joint Clearance

Clearance from manufacturing tolerances or wear is likely to degrade the dynamic performance of connected machine parts. When joint clearance is introduced, the dynamic response of the mechanical system is substantially changed, seen as high acceleration and force peaks and dissipation of energy. Looking at contact models, the simpler ones, such as the linear Kelvin–Voigt or the nonlinear Hertz model, are characterized by a set of parameters. These include material parameters, coefficient of restitution and possibly a coefficient of friction. The analysis models can be divided into two groups – continuous and dis-continuous, related to whether integration is carried out through the period of contact, or stopped and restarted after the impact.Based on the equations of motion for a multibody system of rigid bodies, it is suggested that the continuous analysis approach is combined with a contact force model to describe joint clearance in rotational joints. Performing simulations with this methodology allows not only to quantify the overall mechanism behaviour, but also in-depth analysis of the impact mechanics in the clearance joint. Experimental data from a double pendulum impacting a rigid plate is used to verify the suggested continuous analysis method.     

小型轴流压气机清洗两相流场的数值模拟

针对某小型航空发动机单级轴流压气机的清洗需求,以数值模拟结合实验的方法对压气机清洗流场的各种参数进行了分析研究.在初步确定清洗方案的基础上,建立了基于S-A湍流模型的离散相数值模拟理论模型,以经验公式估算喷嘴形成的初始液滴分布,并对喷嘴的实验参数进行了校准,最后以CFD软件进行了流场的数值模拟,计算结果表明：清洗液滴不会对压气机的流场产生明显影响,平面扇形喷嘴在该小型压气机上能获得较好的清洗效果.     

基于PIC单片机的螺杆式空气压缩机小型控制器

介绍了如何利用Microchip单片机设计的一种空气压缩机监控系统。PIC单片机具有的高稳定性,并且可以选择功能模块适合的型号来以最小的电路规模实现监控功能。软件实现上,主要介绍幕单页面的实现和通过消息机制协调各个功能模块。     

低高度混凝土桥梁裂缝病害分析及处置措施

当低高度混凝土桥梁出现裂缝时,会影响桥梁结构的承载力,降低桥梁结构的耐久性。结合低高度混凝土桥梁裂缝处置措施,分别分析了20 mRC、20 mPC、16 mPC、16 mRC四类低高度桥梁裂缝病害,并提出了合理的建议,采取了适当的处置措施。     

空气压缩机选型软件的研究与实现

空压机选型是空压机产品销售过程中的一个重要环节,其目标是使得用户在选购之前对产品的性能指标有一个全面的了解。基于AR1540标准的计算方法采用C＋＋Builder作为开发工具实现了一套较为复杂的空压机选型软件。     

主成分分析与遗传神经网络在制冷系统故障诊断中的应用

针对低温试验系统制冷设备测点多、数据间存在强相关性等特点,将主成分分析法和遗传神经网络智能识别方法进行组合,引入制冷系统的故障诊断中;结合专家经验和主成分分析客观地对多传感器信息进行了科学合理的故障特征优选,从而确定了神经网络的输入空间;为了克服神经网络易陷入局部最小的缺陷,利用遗传算法的全局搜索能力,对神经网络的初始权值和阈值进行了优化;运用该方法对制冷系统各故障状态进行识别,结果表明,简洁有效的网络结构不仅缩短了训练时间,而且提高了网络的稳定性和分类精度,为监测系统提供了一种有效的故障诊断方法。     

基于PLC的螺杆空压机控制系统的研究与开发

介绍了一种采用PLC作为控制核心器件的螺杆空压机控制系统,充分利用可编程控制器能适应各种恶劣现场条件,安装维护方便,现场抗干扰能力强,提供多种稳定可靠的通讯模式的特点,极大提高系统的可靠性、稳定性和信息化,完全可以满足现场使用要求。     

电容式砂石料位传感器特征的数学模型建立

根据最小二乘估计算法基本原理,提出了用MATLAB语言建立电容式砂石料位传感器料位与相关测量电路输出电压（h—V）关系特征的数学模型的方法,给出了建模的程序、设计步骤以及应用实例。