Whether a hydraulic system works normally, it depends on two main operating parameters that whether the pressure and flow are in normal working state, and whether the system temperature and actuator speed and other parameters are normal or not. The hydraulic system fault phenomenon is various, and the fault reason is also the synthesis of many factors. The same factor may cause different fault phenomena, and the same fault may correspond to many different reasons. For example, oil pollution may cause the hydraulic system pressure, flow or direction fault, which brings great difficulty to the hydraulic system fault diagnosis.

The idea of fault diagnosis by parameter measurement is as follows. When any hydraulic system is working normally, the system parameters are working near the design and set values. In the work, if these parameters deviate from the preset values, the system may fail. The essence of hydraulic system failure is the abnormal change of working parameters. Therefore, when the hydraulic system fails, it must be that some component or some component in the system fails, and it can be further determined that the parameters at a certain point in the loop have deviated from the predetermined value. This means that if the working parameters of a certain point in the hydraulic circuit are not normal, the system has been out of order or may be out of order, and maintenance personnel should immediately deal with it. In this way, on the basis of parameter measurement and logical analysis, the fault can be found quickly and accurately. Parameter measurement can not only diagnose system faults, but also predict possible faults. Moreover, this kind of prediction and diagnosis is quantitative, which greatly improves the speed and accuracy of diagnosis. This kind of testing is direct measurement, and the testing speed is fast. The error is small. The testing equipment is simple and easy to popularize in the production site. It is suitable for testing of any hydraulic system.