Hydraulic cylinder leakage analysis diagnosis method

Abstract

The invention relates to a hydraulic cylinder leakage analysis diagnosis method comprising the following steps: combining wavelet decomposition with wavelet noise reduction, using wavelet analysis todecompose hydraulic cylinder two-chamber pressure signals into four layers, extracting segment pressure signal time domain characteristics, combining a root mean square and a root mean square error ofwavelet decomposition coefficients cA4 and cD2 to evaluate the hydraulic cylinder leakages, thus diagnosing the hydraulic cylinder internal and external small leakage rates. The hydraulic cylinder leakage analysis diagnosis method uses two-chamber pressure sensors arranged in hydraulic cylinder without adding extra sensor, thus effectively detecting the common hydraulic cylinder internal and external leakages, and preventing accident hidden troubles caused by hydraulic cylinder leakage factors.

Description

technical field [0001] The invention relates to the field of fault monitoring of engineering hydraulic equipment, in particular to a diagnostic method for hydraulic cylinder leakage analysis. Background technique [0002] Hydraulic cylinders are commonly used actuators in construction hydraulic machinery, and leakage is the most common failure mode of hydraulic systems. Leakage is divided into two types: external leakage and internal leakage. External leakage will cause environmental pollution and waste of resources. Compared with internal leakage, external leakage is easier to judge. It can be directly judged according to whether there is hydraulic oil leakage; internal leakage will affect the hydraulic cylinder. Insufficient power, slow movement speed, hydraulic cylinder crawling, weak output, unstable work and other phenomena. Leakage will seriously affect the working efficiency and safety of machinery. Therefore, timely identification of hydraulic cylinder leakage can e...

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Problems solved by technology

[0003] However, the internal leakage detection of hydraulic cylinders is a big problem, mainly because the leakage of different hydraulic components varies greatly, ranging from a few milliliters per minute to thousands of milliliters

Traditional leak measurement generally uses a micro flowmeter, but its effective range is limited and it needs to be connected in series in the oil circuit, which is inconvenient to install; moreover, the flow sensor is expensive, and in addition, once the flow sensor is stuck by foreign objects or damaged by fatigue, the pipeline will be blocked , causing serious failure of the hydraulic system

Therefore, there are considerable limitations in practical applications. When the leakage of hydraulic components is very small, it is difficult to accurately test even with high-performance micro flowmeters.

Common hydraulic cylinder leakage fault diagnosis is mainly carried out around the leakage measurement method and hydraulic system leakage model. There are problems such as complex system structure, large adjustment to the original hydraulic system, difficulty in accurate modeling, and high algorithm complexity.

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