【作者】 邵勇；

【导师】 周华；

【作者基本信息】 浙江大学 ， 机械电子工程， 2012， 硕士

【摘要】 过滤器是液压系统中用以控制油液污染度的重要元件,它的作用是滤除油液中的固体颗粒污染物,使油液的污染度控制在关键液压元件能够耐受的限度以内,以保证液压系统的工作可靠性和延长元件的寿命。由于过滤产品暴露的质量问题比较严重,与发达国家产品相比差距很大,过滤产品性能试验日益引起用户及生产厂家的重视。因此,建立过滤器性能测试系统具有重要的现实意义。研制过滤器性能测试系统,不仅能够为开展影响过滤性能因素的研究提供条件保障,同时对液压系统油液颗粒浓度的分析与在线监测以及高精度油温控制技术的深入研究将促使液压系统性能提高。本论文研制了一套过滤器性能测试系统,用于对液压过滤器进行多次通过试验、压降流量特性试验以及滤芯抗流动疲劳特性试验,评定过滤器的各项性能指标,包括过滤精度、压降流量特性、纳污容量以及滤芯的抗流动疲劳特性。论文的主要内容如下：第一章,以国内外文献为基础,分别介绍了过滤器性能测试技术的国内外现状,以及过滤器性能测试试验台的国内外研究进展。简要介绍了研制过滤器性能测试系统的难点问题,阐述了课题的目的与意义、主要研究内容及难点。第二章,从功能需求出发,对过滤器性能测试系统进行了总体设计,包括系统技术指标及评定参数分析、液压回路原理设计和优化、系统技术要求分析以及关键液压元件的选型与设计。针对于设计制造过程中的几个关键技术,油路中试验颗粒的沉降以及尺寸改变问题、试验装置的全电脑控制以及共同试验基准的保证问题,对其进行了阐述并给出了解决方案。第三章,设计开发了过滤器性能测试监测控制系统,包括测控系统信号汇总、上下位机选型、PLC实时监控系统软件设计以及上位机软件设计。PLC实时测控系统软件可以分为四个模块：通讯模块、数据采集模块、数据处理及过程控制模块(含相关控制算法)以及安全保护模块等。上位机软件实现了人机交互界面设计、基于DataSocket技术与OPC服务器通讯、数据处理、试验数据库管理以及试验报表创建等功能。第四章,结合过滤器性能测试系统的结构特点,建立液压系统颗粒污染控制模型,对影响油液颗粒浓度的因素进行了分析,得出滤器上游颗粒浓度维持稳定的条件为保持稳定的系统油液体积。在过滤器性能测试试验台上,开发了油液颗粒浓度在线监测系统,并进行了油液颗粒浓度控制试验。模型计算与试验结果比较表明,两者的趋势基本一致,在一段时间后,滤器上游的颗粒浓度均能够达到平衡状态,且在各个试验点上都非常接近,说明污染控制模型推导过程中所作的假设是合理的,可以用于液压系统颗粒污染物浓度变化的预测和监控。但是在达到平衡状态的时间上,两者相差很大。在保持系统油液体积稳定的情况下,微调污注流量,能够很快地使滤器上游颗粒浓度维持在平衡值附近,快速地满足试验的要求。第五章,针对过滤器性能测试液压系统建立了温度被控对象以及三通比例水阀的数学模型。液压系统油温控制对象是典型的一阶滞后环节,具有大惯性、大滞后以及参数时变等特点。在此基础上,提出了基于参数自整定PID的油液温度控制策略,并在MATLAB/SIMULINK进行了参数自整定模糊PID控制器的设计以及油液温度控制的仿真分析。仿真结果显示,采用参数自整定模糊PID控制算法对液压系统油液温度进行控制,油温静态误差小,且控制器具有不依赖系统模型,对系统时变参数不敏感等优点。将模糊推理规则构造成查询表,存储在PLC中,通过简单的查表与插值计算实现参数自整定模糊PID算法。在过滤器性能测试试验台上进行了油液温度控制试验,变工况下,液压系统油液温度能有效控制在40±2℃范围内。第六章,概括了全文的主要研究工作和成果,并展望了今后需进一步研究的工作和方向。更多还原

【Abstract】 Filters are important components for contaminant control of hydraulic system.Its role is to filter out particles contamination, to keep the oil contamination level within the limit that the key hydraulic components can withstand, to ensure the reliability and extend component life.Recently, due to the exposure of the quality of filtration products, especially filter elements, the problem of performance test for filters causes the user and the manufacture’s attention.Therefore, there is important practical significance to establish a performance test system for filters.The techniques of oil contamination level analysis and on-line monitoring and oil temperature precision control are studied in detail in this thesis.The development and key technology research of a performance test system for filters, not only provides conditions for carrying out the study of filters, but also promotes the performance of hydraulic systems.The system is capable of evaluating filtration performance of a filter element with multi-pass method and evaluating differential pressure versus flow characteristics and determination resistance to flow fatigue using particulate contaminant.The main contents of each chapter are summarized as follows:In chapter 1, the history and current research status of filter performance testing technology and test-bed are reviewed based on a lot of publications and conference papers. Key technology of performance test system is briefly introduced.Accordingly, the research and the goal of the project are brought forward.In chapter 2, according to the functional requirements, the overall design scheme of the performance test system is put forward, including analysis of technical parameter and evaluation indicators, the design of working principle of hydraulic circuit, and selection and design of key components. Several technical difficulties, such as the deposition of particles in the test circuit and size change problem, computer control system and uniform test benchmark to ensure the comparability of test results, are stated and the principles are explained.In chapter 3, the hardware and software of computer control system are developed, including the selection of upper and lower machine, the software development of the submitted-machine, and the software development of the main-machine.In chapter 4, based on the theoretical model for fluid power system contamination control, the influence factors are considered.The condition of remaining filter upstream particle concentration stable is to maintain the system oil volume to remain stable.Contaminate control experiment is made on the performance test system, the experiment results show that filter upstream particle concentration can quickly reach the steady state. In chapter 5, based on the mathematical model of temperature control object and 3-way proportional valve, the difficulties of oil temperature control are analyzed.A kind of oil temperature control strategy based on parameter self-tuning fuzzy PID control method is put forward.The parameter self-tuning fuzzy PID controller is designed.Oil temperature control experiment is made on the performance test system, the experiment results show oil temperature maintaining in 40±2℃.In chapter 6, some conclusions are given and some new views are put forward in the future.更多还原