Hydraulic Servo Valve Test System Based On Virtual Instrument Research

Electro-hydraulic servo valve is the key component of electro-hydraulic servo system, the test of its static and dynamic characteristic is significant in theories and test research of electro-hydraulic servo system. With the development of computer-aided test (CAT) technique, the test technique of electro-hydraulic servo valve has made a great progress, also gone up to a new high level with the appearance of virtual instruments technique. By combining virtual instruments technique with the test technique of electro-hydraulic servo valve, the test system of electro-hydraulic servo valve based on virtual instruments has been developed by the graphics software-LabVIEW6.1. The test principle and method of electro-hydraulic servo valve were discussed in this dissertation. The experimental results on a Moog servo valve demonstrate that the design of electronic-hydraulic servo valve test system is valid.At first the design scheme of the test system of electro-hydraulic servo valve based on virtual instrument was proposed. According to this design scheme, the hydraulic test unit and measurement unit were developed.And then, a method of load-flow low-pressure measurement was proposed in the light of the hydraulic-resistance theory of servo valve. The validity of the method was proved by the experimental results. Therefore, the measurement of the characteristic of load-flow and no-load flow can be realized by using this method.Lastly, a fault diagnosis method based on virtual instrument for electro-hydraulic servo valve was proposed. The expected results have been obtained by the simulated test on the developed test system.The system software is programmed by LabVIEW6.1 with the Windows XP operating system and the interface is friendly and it is simple easy to maintain and maintenance. The signal source and testing functions are attained by the program, andreduces the practice instruments and lowers the expenditure.