| Mechanized cotton harvesting has become the key to the mechanization of the whole process of cotton production.According to the actual production demand of cotton harvesting in Xinjiang,the power shift transmission of cotton picker combined with hydraulic walking transmission scheme is designed.The walking transmission scheme fully combines the smooth shift performance of power shift transmission and the stepless speed regulation characteristics of hydraulic transmission,and is widely used in engineering machinery and agricultural machinery.In order to meet the requirements of efficient and stable operation of cotton picker,according to the requirements of picking and driving operation of cotton picker,this thesis takes the power shift walking transmission system of cotton picker as the research object,and studies the matching of walking transmission system.The research contents are as follows.1、Combined with the power shift theory,the characteristic parameters of the walking transmission system of the cotton picker with high domestic market share are analyzed.Based on the basic operation data of cotton planting mode,the operation speed range of the cotton picker is 0 ～ 8.5 km / h for field picking and 8.5 ～ 27.5 km / h for transportation.The power shift is analyzed and the scheme of power shift transmission of cotton picker is designed.The hydraulic traveling transmission system is analyzed,and the closed volume speed regulating circuit is designed to drive the cotton picker to walk.The power shift transmission combined with the closed volume speed regulation circuit constitutes the overall scheme of the power shift walking transmission system of the cotton picker.2、The kinematics and dynamics of the cotton picker are analyzed.The cotton picker adopts double bridge four-wheel drive.Based on the original design parameters of the cotton picker,the walking and traction power of the cotton picker are calculated.Match the maximum pressure and rated pressure of the hydraulic traveling system with the pressure derating.Based on the matching method with angular power as the core,the effective transmission ratio of cotton picker is calculated,and the calculation and selection of variable pump and variable motor are completed.3 、The AMESim software is used to build the simulation model of the power shift walking transmission system of the cotton picker.The model component parameters are the parameters designed and matched in the previous paper.The three working modes of the cotton picker,field transportation and road transportation are simulated and analyzed.Verify the control logic and transmission ratio parameters of the power shift transmission,the relationship between the walking speed of the cotton picker and the displacement ratio of the variable pump and motor,the speed and torque of the pump and motor,and the change trend of the pressure and flow of the hydraulic circuit in different working modes of the cotton picker.According to the simulation data,the efficiency model of hydraulic walking transmission system of cotton picker is constructed,and the main influencing factors of efficiency are analyzed to ensure that the variable pump and variable motor work under efficient working conditions.Aiming at the fluctuation of speed control of cotton picker in field picking condition,a fuzzy PID speed control model of cotton picker in field picking is established based on MATLAB software.Based on the parameters of hydraulic traveling transmission system and the fuzzy PID controller built by Simulink,the dynamic and steady-state characteristics of field picking speed control of cotton picker are simulated and analyzed.4、The prototype of power shift transmission and cotton picker is built through the matching design of power shift hydraulic walking transmission system.Design the operation speed performance test scheme of cotton picker,and carry out the field operation performance test of cotton picker according to the scheme.The test results show that the walking speed of the cotton picker meets the design requirements.Verify the feasibility of the scheme of power shift transmission and hydraulic walking transmission system of cotton picker and the rationality of parameter matching. |
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