Study On The Measurement And Control System Of Tractor HMCVT Test Bench

As a new type of vari-speed device, the hydro-mechanical continuously variabletransmission (HMCVT) has the advantages of both hydraulic drive and mechanical. Itoffers a continuum of gear ratios between desired limits, which consequently enhancesthe fuel economy and dynamic performance of a vehicle by better matching the engineoperating conditions to the variable driving scenarios, and shows a good applicationprospect in high-power tractors and engineering machinery. Study on the compositionof HMCVT performance test bench, develop its measurement and control system,establish the evaluation method of HMCVT performance, enrich its bench testfunctions, improve the accuracy and level of the test system’s automatic test andcontrol, which has important theoretical significance and practical value for theHMCVT theoretical research and application in engineering equipment.In this thesis, the transmission characteristics of tractor HMCVT has beenreviewed, and an analysis on functions of the bench test system is performed. Thestructure and principle of the test rig is designed. According to the concerned industrialengineering standard and the evaluation method on the HMCVT’s performance, theoverall structure of the test system is designed. By analyzing the structure and workingprinciple of tractor HMCVT test-bed system, the function of the measurement andcontrol system is designed. And the selection and analysis of the main components oftest platform, such as power source or load simulation system, has been finished in thethesis. According to the multifunctional characteristic of the measurement&controlsystem and its numerous types of test parameters, a computer control system based onfieldbus technology has been employed in the test bench, the hardware configurationof the control system is carefully finished, and the test software is compiled withLabVIEW based on virtual instrument technology. Finally, the stepless speedregulation characteristic test is being used as an example for illustration to explain thedebugging process of the whole system. The field test results indicate that, the system structure design is reasonable, can meet the requirements for the tractor HMCVTperformance test.