| In the fault diagnosis of hydraulic system, traffic signal is one of the important parameters which is needed to measure and control. Flow measurement usually includes the measurement of the hydraulic system steady mean flow and dynamic flow. Among them, the use of low pressure meter which is arranged in the back of the oil pipe can realize the measurement of the average steady flow, and detect the total amount of leakage, but the dynamic flow of the high pressure side of the system test results are not ideal. How to make a more precise measurement of the high pressure side of the system dynamic flow test restricts the development of hydraulic test system. When the primary instrument is determined, The dynamic characteristics of flow meter is also affected by the secondary instrument. Volumetric flow meter has the characteristics of small flow pulsation and good dynamic characteristics, therefore, this paper mainly studies the feasibility of volumetric flow meter used in high pressure hydraulic system dynamic flow test in high pressure hydraulic system. Myself work was summarized in this paper as follows:Firstly, static characteristic and dynamic characteristic of flowmeter’s measurement was analyzed in this paper. Introduces the composition of the flow measurement system, and combining the flow measurement characteristics from the aspects of hardware and software for dynamic flow measurement. Redesigned the multi-functional gear flowmeter speed detection test bench, through the simulation experiment platform of multiple sets of contrast experiments, some about the sensor type, shell material, selection of gear parameters such as beneficial conclusion, for further experimental study of the flowmeter to offer help.Secondly, designed with PLC control inverter, the inverter control motor, motor drive gears, traffic signal to realize dynamic simulation, based on LabVIEW of the gear dynamic speed measurement procedures was written in this paper. The experimental results show that the frequency of the dynamic signal which is measured by gear flow meter can reach11.1Hz.Bypass method of flow measurement was set up for this research, we numerical simulate the Influence of bypass throttle valve spool structure to dynamic flow signal measurement of system by Fluent. The simulation results show that, he throttle valve which used poppet has little effect on the flow signal of system, which makes the series of micro flow meter in the branch of the main oil system can better detect the change of flow rate, finally, verify the feasibility principle bypass method of flow measurement.At last, we build a comprehensive test-bed with a servo valve and a flowmeter. Then we introduce the composition and working principle of the test-bed, in the meantime, we introduce the its function which include flow calibration and dynamic test of flowmeter in detail. We put forward the mentality which can be used in the measuring the system transient flow by dynamic hydraulic cylinder and analyze the feasibility of the mentality. |
