Study On Fuzzy Reliability Analysis And Fault Search Strategy Of Hydraulic System Of Aerial Work Vehicle

With the development and progress of science and technology,the number of aerial work vehicles is increasing.At present,aerial work vehicles are widely used in gardens,municipal services,ships,ports and other places.In recent years,aerial work vehicles can be seen everywhere in many infrastructure projects,which plays a vital role in China's economic construction.The performance of aerial work vehicle is related to the stable development of the enterprise and the personal safety of the operators,and the key to its performance lies in the hydraulic system,so it is necessary to carry out reliability analysis and research on its hydraulic system.It is not only the enterprise's pursuit but also our expectation to reduce the occurrence of aerial work vehicle accidents and to quickly search for and eliminate faults during the maintenance phase.In this paper,the hydraulic system of working device of aerial work vehicle is taken as the research object,and the hydraulic system of telescopic device is taken as the key analysis object in reliability analysis.First of all,the event that is prone to failure in actual work is selected as the top event,and the fault tree model is established based on the failure situation and historical data in actual work.Secondly,due to the hidden and multiple characteristics of hydraulic system,fuzzy set theory and Bayesian network are introduced to transform fault tree into Bayesian network model.For the problem that it is difficult to accurately obtain the failure rate of bottom event in fault tree,fuzzy set theory combined with expert evaluation method is used to obtain the value of failure rate of bottom event.Finally,the failure probability of the top event and the importance of the bottom event are calculated by using the powerful reasoning function of Bayesian network,so as to carry out a comprehensive reliability analysis on each hydraulic system.In the analysis and calculation,LABVIEW is used to compile the calculation program to facilitate the calculation.In the later period,the adjustment of the failure probability and conditional probability table of the bottom event can also quickly obtain the results through the program.The search strategy for the cause of the failure of aerial work vehicles and the sequence of detection have an impact on the efficiency of maintenance.In the research of search strategy,the hydraulic system of luffing device is taken as the analysis object.On the basis of reliability analysis,combined with the multi-attribute decision method of grey fuzzy theory and multi-attribute decision theory,the critical importance of Bayesian network and the cost of search cost are taken as the evaluation indexes of fault search,and the judgment matrix of fault search is established to study the optimal fault search strategy of the system.Finally,the optimal fault search order of top events under different fault degrees is obtained,which provides guidance for the fault maintenance of equipment.According to the comparative analysis of the actual engineering situation,it is feasible to use the conclusions of the above methods to guide the reliability analysis and fault diagnosis strategy of aerial work vehicles,which not only provides theoretical guidance for the fault diagnosis and maintenance decision of aerial work vehicles,but also improves the maintenance efficiency and saves the maintenance cost.