Research On Fault Diagnosis Research Method For Luffing Hydraulic System Of Lorry-mounted Crane

The continuous development of science and technology promotes the intelligentization of major equipment,including construction machinery.In order to ensure its reliability,equipment health detection has become a research hotspot.As the main component of construction machinery,hydraulic system is particularly important to ensure its reliability in the operation process.At present,there are three common methods for hydraulic health detection,which are knowledge-based,data-driven and physical model-based.Knowledge-based health detection method is suitable for qualitative reasoning and requires high experience and knowledge reserves.Data-driven health detection method requires a large number of fault or life cycle data.In view of the limitations of the two methods,the health detection method of the hydraulic system based on the model has obvious advantages.The accurate mathematical model of the system is used to carry out the health detection of the system.In this paper,the variable amplitude hydraulic system of the lorry-mounted crane is taken as the research object.Firstly,the fault characteristics of the variable amplitude hydraulic system are analyzed,and the simulation and injection scheme of typical faults are proposed.The feasibility of the proposed scheme is verified by simulation.Secondly,the modeling method of power bond graph and analytical redundancy relationship is analyzed,and a model-based fault diagnosis method based on the combination of bond graph and analytical redundancy relationship is proposed.In order to verify the feasibility of the method,a fault diagnosis simulation model based on Simulink is further built.Results show that the proposed fault diagnosis method is reasonable.The main research work is as follow:(1)The working principle of the variable amplitude hydraulic system of the lorry-mounted crane is analyzed,and the typical faults of the system are analyzed.Several typical fault simulation and injection schemes are proposed.The fault simulation model is established by using AMESim software,so as to verify the feasibility of the proposed fault simulation scheme.(2)The modeling principle of power bond graph is analyzed.Based on the bond graph,the model of hydraulic system is established,and the constitutive relationship of each node is analyzed.(3)Based on the basic principle of analytical redundancy relation theory,a model-based fault diagnosis method combining bond graph and analytical redundancy relation is proposed,which mainly includes three parts: residual generation,residual estimation and fault diagnosis.(4)The rationality of the fault diagnosis method is verified.According to the mathematical model derived from the bond graph and analytical redundancy theory,the fault diagnosis simulation model of the hydraulic system is built in Simulink,and the existence and location of the fault are judged according to the simulation results.(5)The rationality of the fault diagnosis simulation model is verified.The fault simulation of the hydraulic circuit with or without fault is simulated on the experimental platform of the lorry-mounted crane.The rationality of the fault simulation model in the fault diagnosis based on the model is verified by comparing the experimental curve with the simulation curve.