Research On The Shift Control System Of Heavy-duty Hydraulic Automatic Transmission

The heavy-duty hydraulic automatic transmission has good torque capacity and shift quality,and is mainly used in heavy-duty vehicles,oil and gas exploration equipment,rail transit,construction machinery and special vehicles.The shift control system of the heavy hydraulic automatic transmission is the "brain" in the shifting process.The collected data is input to the central processor through the signal acquisition circuit.After a series of analysis and calculation,the output signal is selected to the shift solenoid valve.Studies have shown that a good shift strategy can be achieved not only by reducing the fuel consumption rate but also by reducing shift time and impact while meeting the vehicle’s dynamics.This paper is based on the MA5711 heavy-duty hydraulic automatic transmission of Guizhou Kaixing Hydraulic Transmission Co.,Ltd.,which has carried out in-depth research on the shift control system,and provided technical support and theory for the technical research of the heavy-duty hydraulic automatic transmission shift control system in China.Based on the kinematics and dynamics theory analysis of the heavy hydraulic automatic transmission,this paper analyzes the power transmission route of each gear.The structure of the transmission is composed of planetary gear trains.This paper establishes the equation of motion of the planetary gear mechanism and solves it.The gear ratio of each gear is out.Through the dynamic study of the shifting process,the parameters in the torque phase and the inertia phase during the shifting process are analyzed.The corresponding mathematical model was established by studying the characteristics of each component.The improved transmission ratio was optimized by the improved dichotomy.The optimized verification results show that the optimized gear ratios satisfy the dynamics.The fuel consumption rate is reduced,the driving power loss rate is lowered,and the performance of the entire vehicle is greatly improved.A fuzzy shift control strategy was developed and a fuzzy controller was built.Taking the throttle opening and the vehicle speed as two-parameter input,after fuzzy inference and anti-fuzzification,the output of the best gear is selected to select the appropriate engagement clutch,and the whole vehicle simulation of the heavy hydraulic automatic transmission shift control system is built using MATLANB/SIMULINK.According to the simulation results,the designed fuzzy controller can realize automatic shifting,and can ensure that the vehicle can reach a higher speed in time.When the vehicle is in the low gear position,the acceleration is large,which shortens the time for the vehicle to accelerate and improves.Based on the simulation model of the whole vehicle shift control system,the hardware circuit of the whole vehicle shift control system is designed by signal acquisition module,signal processing module,power supply module,gear output module,gear display module and anti-interference module.And wrote the corresponding part of the software program.The fuzzy shift controller inputs the throttle opening and the vehicle speed.In this paper,the Hall sensor is used to measure the vehicle speed,the throttle opening is selected as the magnetoresistive sensor,and the analog-to-digital conversion circuit is designed based on the ADC0808 analog-to-digital converter.The data is transmitted to the central processor,and the fuzzy shift control algorithm based on C language outputs the control signal to the shift solenoid valve and the digital tube to complete the whole vehicle shifting,and realizes the intelligent shifting function of the heavy hydraulic automatic transmission.