Design And Research On Control System Of Hydro-mechanical Continuously Variable Transmission For Cotton Picker

Hydro-mechanical continuously variable transmission(HMCVT)is a transmission method that combines hydraulic and mechanical subsystems.The transmission fully combines the continuous speed characteristics of the hydraulic system and the high efficiency characteristics of the mechanical transmission,so it is widely used in engineering equipment and agricultural machinery.In order to meet the requirements of the cotton picker for efficient and stable work,according to the picking and driving requirements of the cotton picker,we took the self-developed hydraulic mechanical continuously variable transmission as the research object,and further studied the control system in the transmission system of the cotton picker.The research content is as follows:1、Combining the transmission requirements of the cotton picker,this article analyzes the transmission principle and characteristics of the hydraulic-mechanical continuously variable transmission,so as to obtain the transmission scheme of the hydraulic-mechanical continuously variable transmission of the cotton picker,and then analyzes the principle of the transmission control system,So we put forward the appropriate control system design requirements.Based on the AMESim software,the whole vehicle model of the hydraulic-mechanical CVT of the cotton picker is established,including the pump motor hydraulic system model,mechanical transmission model,picking system model,vehicle environment,clutch control and other models,combined with engine external characteristic parameters,using experimental modeling Methods The engine control model was constructed,and the engine and the whole machine model were simulated and analyzed.The simulation results showed that the HMCVT of the cotton picker can realize continuous shifting under different working conditions.2、According to the design requirements of the HMCVT control system of the cotton picker,the overall structure and control logic of the control system are established.In order to meet the control requirements,the control system is designed based on the selection of various sensors,in order to achieve the control performance of the system and To ensure the change of the output speed of the transmission,the C language-based variable pump displacement change program and the flow pressure and speed acquisition program are compiled.The measurement and control system is developed using LabVIEW to realize the communication and monitoring between the upper computer and the lower computer.3、Study the variable speed performance of variable pumps and motors,use simulation and experiment to analyze the efficiency characteristics,ensure the stability of HMCVT output speed,use point-position control to test the relationship between different control voltages and different speed ratios of HMCVT Analyze and study the stable performance of input and output.According to the neural network theory,use Matlab/Simulink toolbox to establish a neural network PID control scheme,and carry out simulation analysis on the output speed of the transmission,verifying the self-adaptive characteristics of the transmission under working conditions and speed,and it has good adaptability and robustness.4、Study the working mode of the cotton picker,aiming at the different output characteristics of the picking speed and the driving speed,use direct control,ordinary PID,fuzzy PID control and other control algorithms to compare and analyze the stability matching study of the picking and driving of the cotton picker.A constant speed coordinated control scheme based on the picking subsystem of a single pump controlled double motor of the cotton picker and the driving subsystem of a variable pump controlled motor.The research results show that the adaptive cooperative control of picking and driving improves the picking and driving performance of the cotton picker.Synchronous stability enhances system control performance;and builds test benches and test bench control systems based on engines,transmissions,and loads,and compares and analyzes the fuel consumption and efficiency of cotton pickers using hydraulic-mechanical continuously variable transmissions through simulations and experiments.To meet the driving requirements of the cotton picker under the picking operation.