Shift Schedule Research On Power Gearshift Transmission Of Tractor

Along with the advance of science and technology, the electronic and intelligent process of tractor products also is in rapid development. As an important indicator of tractor intelligence, active research and innovation on automatic shift schedule are done by many countries. Study of ordinary straight shift schedule, has made certain achievements. However,Study of shift schedule aiming at bend and various special conditions, has made few achievements. Settlement of ordinary shift schedule adaptability under different conditions, not only can improve the safety and fuel economy of vehicles, but also can reduce frequent shift and prolong the service life of speed control system, and it has important theoretical significance and practical value for the innovation to upgrade and intelligent ascension of tractor products.In this article, based on YTO-1804 as the research object, vehicles, drivers and external environment were regarded as a closed loop system, speed, throttle opening and drive roller skating rate were selected from many factors affecting shift time as shift control parameters, dynamic three parameters shift model and economic three parameters shift model were formulated with solving by graphic method and analytic method. At the same time, comprehensive shift strategy balancing dynamic and economic needs was puts forward. Aiming at the possible imperfection of the formulated shift schedule under special conditions, those problems of frequent shift on bumpy road, security for bend transfer, poor fuel economy for turning at the edge of field were focused on the research. On this basis, fuzzy control downshift rule, shift modification rule of bend security, and modification rule for turning at the edge of field are presented. To verify the feasibility of presented modification rule, simulation was made by using Matlab/Simulink simulation software. The results showed that the modified shift schedule, on inheriting the advantages of traditional three parameters shift schedule, reduced frequent shift, improved bend safety and fuel economy. Research results of this article can provide a reference for the theoretical perfection and practicability of the shift schedule.