Research On Fault Diagnosis For Shape Control Hydraulic System Of Rolling Mill

With the continuous development of industrial modernization,the demand for steel in the market is increasing,and the requirements for specifications and performance of steel are getting higher and higher.The shape is an important index to reflect the quality of steel products.The shape control system of rolling mill is a system which integrates machine,electricity and hydraulics.Its structure is complex and its faults are numerous.And its operating state has an important impact on steel quality and even property safety.This subject takes the shape control hydraulic system of rolling mill as the research object,studies its working principle and failure mechanism,and builds the system simulation model.Aiming at the fuzziness of hydraulic system faults,this thesis summarizes the knowledge of relevant fields and studies the intelligent fault diagnosis method of the system.This thesis studies the development history and principle of the shape control hydraulic system of rolling mill,understands the control process of the bending roll and the shifting roll technology,and analyzes and summarizes the fault mechanism of the hydraulic system.Based on these researches,a model of the shape control hydraulic system of rolling mill is proposed,and AMESim and MATLAB simulation software are used to realize the joint simulation.By modifying the parameters of the model and other means to simulate various faults of the system,the problem of small sample size faced in fault diagnosis research is solved,which provides a basis for more knowledge acquisition.Because fault feature extraction is an important part of fault diagnosis,this thesis also introduces the analysis and processing methods of system state signals,and focuses on the application of wavelet analysis technology in the analysis of hydraulic system state signals.The expert system has the advantages of flexibility and enlightenment,so this thesis selects it as the intelligent fault diagnosis method for the shape control hydraulic system.Aiming at the insufficiency of expert system in the fuzzy diagnosis of hydraulic system,this thesis determines the expert system diagnosis method based on fuzzy theory and its basic structure through the research of fuzzy theory and related fault diagnosis technology.Apply feature extraction and other technologies to acquire knowledge contained in simulation experiment data,and expressing it with the expert experience in the form of production rule combined with fuzzy logic,and designing the corresponding data table to store the rules in the database.Determine the fuzzification method of the fault feature or symptom,improve the fuzzy matching algorithm,and select the matching rule in the knowledge base.Then this thesis constructs the fuzzy relation matrix,determines the fuzzy synthesis operator,and then deduces the cause of the fault and its membership degree.Then,the diagnosis results are output by means of the maximum membership principle and other de-fuzzification methods to construct an effective fuzzy inference mechanism.Finally,based on the research of the related theory and technology,this thesis uses C#programming language and Microsoft SQL Server database management system to design and develop the corresponding functional modules and corresponding interfaces of fuzzy expert system,and verifies the intelligent fault diagnosis function of the software through diagnostic examples.