Research On The Variable Speed Pump Output Pressure And Flow Rate Of Soft Measurement Method

Pressure and flow in the hydraulic transmission and control technology are two important parameters in the hydraulic system.In the actual hydraulic control system, whether power efficiency calculation, condition monitoring, fault diagnosis, or to control the load all need to measure flow or pressure of the system. All the control way need to be done on the system pressure or flow for quickly, conveniently and accurately measurement. Most traditional pressure measurement use sensing element and contact with the oil phase, although can solve the problem of the measuring precision and rapidity, but also brought new problems, such as the installation is inconvenient, the oil flow disturbance etc; Most of the traditional flow measurement used more movement components in contact with the oil phase, using the mechanical principle of indirect measurement of flow, because of the element movement itself exists inertia and the complexity of the oil properties and fluid flow state, it is difficult to fast and accurate measurement of flow.This paper introduces a kind of pressure and flow rate based on virtual instrument technology of soft measurement method in detail, using direct acquisition parameters associated with pressure and flow rate, real time operation by the software, indirectly by measuring pressure and flow signal. Experiments prove that the soft measurement method of pressure in terms of accuracy and speed of response are to meet the test requirements. soft measurement method of flow measurement accuracy not only meet the test requirements, and the response rate was significantly better than the conventional turbine flow sensor. By using this method can convenient to realize the pressure and flow of the system of synchronous measurement.In this paper, the main research work are as follows:1) Establishing permanent magnet servo motor driven pump quantitative mathematical model of the hydraulic power system, including the permanent magnet synchronous motor, gear pump and proportional relief valve load simulation mathematical model.2)According to the permanent magnet servo motor driven pump hydraulic power system dynamic quantitative relationship establish initial pressure and flow rate of the soft measurement mathematical model and to modify the model.3)Using Matlab simulation to find out and variable speed pump output pressure and flow rate directly or indirectly related factors, and provide the basis for the soft measurement to choose the appropriate parameter, but also to verify the feasibility of soft measurement model.4)Using LabVIEW virtual technology, to realize the pressure, and flow rate online measurement on the test table.5)Respectively for pressure and flow rate of soft measurement model for static analysis, dynamic analysis and evaluation.6)In the application of flow closed-loop control and fluid transient power monitoring base on the soft measurement model.