Research On Fault Diagnosis And State Recognition For Large Water Press Based On Multi-source Information Fusion

Large hydraulic press is a strategical equipment of independent industrial system construction and national defence, its safety and reliability is crucial. As an import supporting technology of ensuring that the large hydraulic press operate safely and reliably and its maintenance actives are organized by the scientific and reasonable manners, research on the fault diaguosis and state assessment are of quite significance.The present research on large hydraulic press fault diaguosis and state assessment has two main issues that are not satisfactorily solved. One is the mechanisam and degradation laws of typical faults, which are important for fault diaguosis and state assessment is seldom investigated. The other is the shortage of diagnositic technologies. For example, it is quite difficult to carry out the missions of fault diagnosis and state assessment accurately using traditional single sensor imformation because of a series of special characteristics of large hydraulic press including complicated structures, poor operational environments and large disturbance of observation parameters.Supported by the projects "Research on condition monitoring and fault diaguosis of300MN hydraulic press", which belong to national high technolgoty research and development program of China (NHTRDPC,863Program), the opening/closing fault of high pressure and large flow capacity water valve and extraordinary column stress in large hydraulic press are taken as research objects in this paper. The mechanisams of the faults are investigated systematically using multidisciplinary complex simulation technique. Then based on previous work, the technology of fault diaguosis and state assessment based on multi-source information fusion are studied. The main purpose of the research work is to investigate the new approaches to deal with the problems of fault identification and state assessment accurately for large hydraulic press. At the same time, also aims at providing valid technical support for health management of large hydraulic press. The detailed contents and innovatie works are shown is the following sections.1. The system dynamic characteristic and mechanism of typical fault under the condition of serious coupling in large hydraulic press are analyzed systematically(1) A complex system dynamics model integration of fluid power, machinery and control is build using multidisciplinary complex simulation technique. The system dynamic characteristics under condition of serious coupling in large hydraulic press are analyzed systematically. The working mechanism and characteristic of large hydraulic press in normal working condition which provides a theoretical basis for fault diagnosis and condition assessment are revealed.(2)Factors for opening/closing fault formation under complex environment in high pressure and large flow capacity water valve are analyzed qualitatively and quantitatively. Fault characteristics, evolution law and how the faults influence the large hydraulic press in condition of serious coupling in large hydraulic pressare are analyzed systematically through fault simulation. Then based on these research works, the sensitivity of fault characteristic parameters which are important for fault diaguosis and state recognition are analyzed.(3)Using modern CAE finit element modeling simulation analysis method, the contact mechanics hehaviour between moving beam and column in large hydraulic press is analyzed. The mechanism, distribution and parameter influence of additional column stress are revealed. A calculation method for additional column stress calculation which is important for column stress state assessment and transfinite diagnosis is put forward.2. The technology of fault diaguosis and codition assessment in large hydraulic press based on multi-source information fusion are studied deeply.(1)The reference value of fault feature parameters under different opening/closing fault conditions in high pressure and large flow capacity water valve are obtainted through physical modeling and numerical simulation. Then based on these research works, a feature parameter standard model of opening/closing fault in high pressure and large flow capacity water valve is put forward.(2) The grey system theory and method is applied in multi-source information fusion fault diagnosis and codition assessment in high pressure and large flow water valve. A quantitative detection approach for opening/closing fault in high pressure and large flow capacity water valve is put forward, and a state assessment method for high pressure and large flow capacity water valve based on grey clustering is put forward. The methods are applied effectively in300MN die hydraulic press which demonstrates the effectiveness of the methods.(3)Based on data redundancy and complmentarity, a detecting data redundancy check method and a state assessment method for column stress are put forward. Experiment study is made which demonstrates the effectiveness of the methods.3. The key technologies of condition monitoring in large hydraulic press are studied and integrated. A condition monitoring and fault diagnosis based on multi-source information fusion is designed and applied in300MN die forging hydraulic press.(1)In view of the special structure and and working environment in large hydraulic press, the key technologies of non-functional parameter detecting methods such as column stress and crossbeam offset in non-working directions are studied.(2)300MN forging hydraulic press is taken as the object, a condition monitioring and fault diagnosis based on multi-source information fusion is designed using the theory and technology studied in this paper. The successful apply of the system improve the safety and reliability of300MN die forging dydraulic press.