With the rapid development of hydraulic technology, hydraulic systems have become more complex, and the detection of internal leakage is becoming more and more difficult. A fast and accurate approach is required to detect the internal leakage of a hydraulic system. This article describes the theory and application of the internal leakage detection of open-circuit hydraulic systems based on Active Hydraulic Test Technology. The theory of Active Hydraulic Test Technology is introduced, a leakage model and an online detection model of an open-circuit hydraulic system are established, and the total leakage of the hydraulic system is theoretically analyzed. A theoretical analysis of the leakage test method for the main control oil circuit and branch components is also conducted. Through applied research on a hydraulic system of a 1,250-ton forging machine, the effectiveness of the method for detecting the internal leakage fault of a complex hydraulic system is verified.
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