| The hydraulic pump and motor are the core components in the hydraulic transmission system.Its reliability and comprehensive performance are the key factors for ensuring the stable and efficient operation.Therefore,it is very important to test the reliability and comprehensive performance of the hydraulic pump and motor.However,the current test rigs of hydraulic pumps and motor only test for comprehensive performance generally,and have problems such as poor test accuracy,high energy consumption,and low test efficiency.Therefore,the research and development of hydraulic pump and motor test system with high accuracy,low energy consumption,and high efficiency has great practical significance.This paper uses hydraulic computer aided testing(CAT)technology to develop a comprehensive measurement and control system for hydraulic pump and motor reliability and performance testing.The system takes the industrial control computer as the core,controls the power unit and safety auxiliary unit separately through the ACS880 frequency converter and the PLC,uses the NI board to realize the signal acquisition and the control,and develops the upper computer software based on LabVIEW,has the manual and the automatic two kinds of test methods,And it can realize multi-station test at the same time,the test efficiency and precision are both higher.Firstly,according to the requirements of positioning and testing accuracy and efficiency,the paper carries out the analysis of the test rigs requirements,determines the main technical indicators,and designs the overall plan,which mainly includes the hydraulic test circuit,the overall layout of the test rigs,and the measurement and control system.Secondly,the construction process of the measurement and control system hardware platform is discussed.The hardware selection of the power control unit and the data acquisition and control unit,the design of the measurement and control circuit and the internal layout of the control cabinet are mainly described.Besides,the upper and lower computer software of the measurement and control system was developed,and the upper and lower computer communication was realized based on the OPC protocol.The entire measurement and control software was developed using modular ideas.Based on LabVIEW,the host computer software was developed and the lower computer program was written in STEP7.This paper focuses on the interface design and programming of the main functional modules,and studies the signal filtering methods.Then the PLC program editing is introduced.In addition,the simulation and experimental study of the power control unit are carried out,and the fuzzy PI direct torque control method is used to control the main drive.This paper compares the traditional PI and fuzzy PI speed control,establishes its mathematical model and simulation model,and analyzes the simulation results.It can be concluded that the performance of the fuzzy PI direct torque control is better than that of the traditional direct torque control,then the correctness of this conclusion was verified by experiments.Finally,the control system of test-bed is debugged by the manual and automatic test modes respectively.The variable characteristics test of the load sensitive pump and the hydraulic pump and the motor impact test are analyzed in detail.The performance of the measurement and control system is tested. |
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