液压系统故障诊断外文文献翻译.doc

1、附录 1故障诊断液压传动系统由于其独特的优点，即具有广泛的工艺适应性、优良的控制性能和较低廉的成本，在各个领域中获得愈来愈广泛的应用。但由于客观上元、辅件质量不稳定和主观上使用、维护不当，且系统中各元件和工作液体都是在封闭油路内工作，不象机械设备那样直观，也不象电气设备那样可利用各种检测仪器方便地测量各种参数 ,液压设备中，仅靠有限几个压力表、流量计等来指示系统某些部位的工作参数，其他参数难以测量，而且一般故障根源有许多种可能，这给液压系统故障诊断带来一定困难。在生产现场，由于受生产计划和技术条件的制约，要求故障诊断人员准确、简便和高效地诊断出液压设备的故障；要求维修人员利用现有的信息和现场的

2、技术条件，尽可能减少拆装工作量，节省维修工时和费用，用最简便的技术手段，在尽可能短的时间内，准确地找出故障部位和发生故障的原因并加以修理，使系统恢复正常运行，并力求今后不再发生同样故障。液压系统故障诊断的一般原则正确分析故障是排除故障的前提，系统故障大部分并非突然发生，发生前总有预兆，当预兆发展到一定程度即产生故障。引起故障的原因是多种多样的，并无固定规律可寻。统计表明，液压系统发生的故障约 90%是由于使用管理不善所致为了快速、准确、方便地诊断故障，必须充分认识液压故障的特征和规律，这是故障诊断的基础。以下原则在故障诊断中值得遵循（1）首先判明液压系统的工作条件和外围环境是否正常需首先搞清是

3、设备机械部分或电器控制部分故障，还是液压系统本身的故障，同时查清液压系统的各种条件是否符合正常运行的要求。（2）区域判断根据故障现象和特征确定与该故障有关的区域，逐步缩小发生故障的范围，检测此区域内的元件情况，分析发生原因，最终找出故障的具体所在。（3）掌握故障种类进行综合分析根据故障最终的现象，逐步深入找出多种直接的或间接的可能原因，为避免盲目性，必须根据系统基本原理，进行综合分析、逻辑判断，减少怀疑对象逐步逼近 ,最终找出故障部位。（4）验证可能故障原因时，一般从最可能的故障原因或最易检验的地-0-方开始，这样可减少装拆工作量，提高诊断速度。（5）故障诊断是建立在运行记录及某些系统参数基础

4、之上的。建立系统运行记录，这是预防、发现和处理故障的科学依据；建立设备运行故障分析表，它是使用经验的高度概括总结，有助于对故障现象迅速做出判断；具备一定检测手段，可对故障做出准确的定量分析。故障诊断方法日常查找液压系统故障的传统方法是逻辑分析逐步逼近断。基本思路是综合分析、条件判断。即维修人员通过观察、听、触摸和简单的测试以及对液压系统的理解，凭经验来判断故障发生的原因。当液压系统出现故障时，故障根源有许多种可能。采用逻辑代数方法，将可能故障原因列表，然后根据先易后难原则逐一进行逻辑判断，逐项逼近，最终找出故障原因和引起故障的具体条件。故障诊断过程中要求维修人员具有液压系统基础知识和较强的分析

5、能力，方可保证诊断的效率和准确性。但诊断过程较繁琐，须经过大量的检查，验证工作，而且只能是定性地分析，诊断的故障原因不够准确。为减少系统故障检测的盲目性和经验性以及拆装工作量，传统的故障诊断方法已远不能满足现代液压系统的要求。随着液压系统向大型化、连续生产、自动控制方向发展，又出现了多种现代故障诊断方法。如铁谱技断，可从油液中分离出来的各种磨粒的数量、形状、尺寸、成分以及分布规律等情况，及时、准确地判断出系统中元件的磨损部位、形式、程度等。而且可对液压油进行定量的污染分析和评价，做到在线检测和故障预防。基于人工智能的专家诊断系断，它通过计算机模仿在某一领域内有经验专家解决问题的方法。将故障现象

6、通过人机接口输入计算机，计算机根据输入的现象以及知识库中的知识，可推算出引起故障的原因，然后通过人机接口输出该原因，并提出维修方案或预防措施。这些方法给液压系统故障诊断带来广阔的前景，给液压系统故障诊断自动化奠定了基础。但这些方法大都需要昂贵的检测设备和复杂的传感控制系统和计算机处理系统，有些方法研究起来有一定困难，一般情况下不适应于现场推广使用。下面介绍一种简单、实用的液压系统故障诊断方法。基于参数测量的故障诊断系统一个液压系统工作是否正常，关键取决于两个主要工作参数即压力和流量是否处于正常的工作状态，以及系统温度和执行器速度等参数的正常与否。液压系统的故障现象是各种各样的，故障原因也是多种

7、因素的综合。同一因-1-素可能造成不同的故障现象，而同一故障又可能对应着多种不同原因。例如：油液的污染可能造成液压系统压力、流量或方向等各方面的故障，这给液压系统故障诊断带来极大困难。参数测量法诊断故障的思路是这样的，任何液压系统工作正常时，系统参数都工作在设计和设定值附近，工作中如果这些参数偏离了预定值，则系统就会出现故障或有可能出现故障。即液压系统产生故障的实质就是系统工作参数的异常变化。因此当液压系统发生故障时，必然是系统中某个元件或某些元件有故障，进一步可断定回路中某一点或某几点的参数已偏离了预定值。这说明如果液压回路中某点的工作参数不正常，则系统已发生了故障或可能发生了故障，需维修人

8、员马上进行处理。这样在参数测量的基础上，再结合逻辑分析法，即可快速、准确地找出故障所在。参数测量法不仅可以诊断系统故障，而且还能预报可能发生的故障，并且这种预报和诊断都是定量的，大大提高了诊断的速度和准确性。这种检测为直接测量，检测速度快，误差小，检测设备简单，便于在生产现场推广使用。适合于任何液压系统的检测。测量时，既不需停机，又不损坏液压系统，几乎可以对系统中任何部位进行检测，不但可诊断已有故障，而且可进行在线监测、预报潜在故障。-2-附录 2Fault diagnosisHydraulic driving systembecauseof its unique advantages,tha

9、t is, haswide adaptability, good processcontrol performanceand relatively low cost, get more and more widely usedin various fields. But becauseobjectively yuan, auxiliary parts quality is not stable, and the subjective improper use, maintenance,and the componentsandworking fluid in the systemarewith

10、in the closedoil circuit work,not as intuitive as machinery and equipment, also dont like electric equipment, can use various instrumentation easily measure various parameters, hydraulic equipment,only by a few to indicate that the systempressuregauge,suchassome parts of the working parameters,other

11、 parametersare difficult to measure,andgenerally there are many possiblefault source,which brings certain difficulty for the hydraulic systemfault diagnosis.At the sceneof the production, due to the restriction of the production plan and technical conditions, the required fault diagnosis is accurate

12、, simple and efficient fault diagnosisof hydraulic equipment;For maintenancepersonneluseof existing information and the sceneof the technical conditions, as far as possible reducethe mounting workload, savetime and cost of maintenance,with the most simple technology,in the shortestpossible time, acc

13、urately find out the causeof the failure positions and failure and repair, make the system back to normal operation,andstrive to the samefailure will not happenin the future. The generalprinciples of the hydraulic systemfault diagnosisCorrect analysis of the fault is the precondition of troubleshoot

14、ing, most system failure, not sudden, before always have omen, when developing to a certain extent the failure omen. The causeof failure is various, there is no fixed rule can be found. Statistics show that the fault of hydraulic systemof about 90% is caused due to poor management in order to conven

15、iently, quickly and accurately diagnose faults, must fully recognize the characteristics and law of hydraulic fault, which is the basisof fault diagnosis.The following principles in thefault diagnosisis worth following(1) the first identifies the working conditions of the hydraulic systemand the-3-p

16、eripheral environment is normal needto first find out the mechanicalparts of the equipment or the electric controlling part failure, or the fault of hydraulic system itself, at the same time find out whether the various conditions of hydraulic systemin line with the requirementsof normal operation.(

17、2) the judgment according to the fault phenomenonand the characteristics of certain areasrelated to the fault zone, gradually narrowing the scope of the failure detection element in this area, analysis of the causes,finally find out the specific fault.(3) master fault types according to the phenomen

18、on of failure in the end, make a comprehensiveanalysisstep by step further to find the possible causesof a variety of directly or indirectly, to avoid blindness, must be basedon the basic principle of the system, carries on the comprehensive analysis, logic, reduce suspiciongradually approaching,fin

19、ally find out the fault position.(4) validation may be the cause of the problem, from the most likely the cause of the problem or the most easily inspection place, so can reduce the workload, installation to improve diagnosticrate.(5) fault diagnosis is based on the operation records and some system

20、 parameters.Set up a system running records, this is the scientific basis for the prevention, detection and troubleshooting; Set up equipment operation fault analysistable, it is the useof theheight of theexperiencesummarization,helpsto quickly judge the problem; Have a certain detection means,can m

21、ake a accurate quantitative analysisof the fault.Fault diagnosismethodsDaily for hydraulic system fault is the traditional way of logic analysis approach.The basic idea is comprehensive analysis, the condition judgment. The maintenancepersonnel by watching, listening, touching, and simple test and t

22、he understandingof the hydraulic system,from experienceto determine the causeof the failure. When the hydraulic system failure, there are many possible fault source. Using logic algebra method, may be the causeof the problem list, and then one by one according to after the first difficult logic, ite

23、m by item, approximation, finally find out the causeof the problem and causeof failure of the specific conditions.-4-For maintenance personnel in the process of fault diagnosis has a basic knowledge of hydraulic system and strong analytical ability, can guaranteethe diagnosis efficiency and accuracy

24、. But the diagnosis processtrival, must passa large number of inspection, validation, and can only be qualitatively analyzed,the diagnosis of the cause of the problem is not enough accurate. To reduce the blindnessof systemfault detectionand empirical anddisassemblingworkload, the traditional fault

25、diagnosis method has far cannot satisfy the requirements of modern hydraulic system. As the hydraulic system to develop in the direction of large-scale, continuous production, automatic control, appeared a variety of modern fault diagnosis method. Such as iron spectrum technology, can be separatedfr

26、om the oil of various grinding grain quantity, shape,size,composition and distribution rule, and so on and so forth, timely, accurately judge the degree of wear parts of the systemcomponents,form, etc. But also to the hydraulic oil pollution of quantitative analysis and evaluation, the online detect

27、ion and fault prevention.Basedon artificial intelligence expert diagnosissystemis broken, it through the computer imitation in there were experienced experts in the field of the method to solve the problem. Input fault phenomenonthrough the man-machine interface to computer,the phenomenonof computer

28、 accordingto the input aswell as the knowledge in knowledge base,the causesof failure can be calculated, and then through the man-machineinterface and output the reasons,and maintenance plans or preventive measuresare put forward. Hydraulic system fault diagnosis method for such broad prospects,hasl

29、aid a solid foundation of hydraulic system fault diagnosis automation. But most of these methods need expensive testing equipment and sophisticated sensing control system and computer processing system, some methods have some difficult, under normal circumstancesis not suitable for field use. Here i

30、s a simple and practical method of hydraulic system fault diagnosis.The fault diagnosissystembasedon parametermeasurementA hydraulic system work is normal, the key dependson two main working parametersnamely whether the pressure and flow rate is in normal working condition, as well as the system par

31、ameterssuch as temperature and speed of actuator is normal or not. Hydraulic system failure phenomenonis various, the-5-causeof the problem is also a combination of many kinds of factors. The same factors may lead to different fault phenomena,andthe samefault may correspond to a variety of different

32、 reasons.For example: oil pollution may causehydraulic system pressure,the flow or direction and so on various aspectsof fault, which brings greatdifficulties to the hydraulic systemfault diagnosis.Method for measuring the parametersof the thinking of troubleshooting is that any of the hydraulic system working properly, the system parametersin the design and near the set value, the work if these parametersdeviated from the target value, then the systemwill fail or likely to fail. The essenceof a hydraulic system failure is the system working parameterschanges.So when the hydraulic system fai