Performance Analysis And Control Research On Shift Actuator Of Heavy-duty Automatic Transmission

With the rapid development of China’s economy,the demand for heavy vehicles is growing.The research on the key technologies of heavy-duty automatic transmission can not only enhance the development and application ability of heavy-duty vehicle technology,but also improve the international competitiveness of domestic heavy-duty automatic transmission.The performance and shift control of the electro-hydraulic actuator are the key factors affecting the comprehensive performance of the heavy-duty automatic transmission.Through the mathematical modeling of the electro-hydraulic actuator,parameter analysis and the study of Bode plots,the optimization design of the structural parameters of the pressure reducing valve and the clutch,the research on the shift actuator suitable for the heavy-duty automatic transmission is carried out,and the shift control strategy is designed based on the ideal clutch slip speed,which lays the theoretical foundation for improving the comprehensive performance of the heavy-duty automatic transmission.First of all,based on the analysis of the working principle of the electro-hydraulic actuator and the understanding of the mathematical relationship among the proportional solenoid valve,pressure reducing valve and clutch component,the mathematical models of the proportional solenoid valve,pressure reducing valve and the wet clutch under the state of oil filling and oil discharging are established respectively,and the mathematical models of the electro-hydraulic actuator are obtained.By comparing the experimental data with the simulation results,the accuracy of the mathematical model is verified,and the transfer function from the output pressure of the reducing valve to the pressure of the clutch is derived.Then,the force,displacement and speed,the hydraulic power,the flow,pressure,pressure deviation and response deviation of the clutch and the baud diagram are simulated and analyzed.Then,on the basis of the mathematical model of the electro-hydraulic actuator,combined with sensitivity analysis and baud diagram to identify the key parameters of the pressure reducing valve and clutch components,the artificial bee colony algorithm is used to optimize the electro-hydraulic actuator,so as to improve the precise control and rapid response of the clutch pressure.In the aspect of result analysis,the pressure,response time,flow rate,impact degree,acceleration of clutch piston,steady-state hydrodynamic force and oil temperature rise were compared before and after optimization.Finally,considering the uncertainty of the parameters of the electro-hydraulic actuator,the change of the friction coefficient with the slip speed of the clutch,and the complex and variable driving conditions of the vehicle,a robust control strategy consisting of a feed-forward controller,a feedback controller and an interference controller is designed to track the ideal slip speed of the clutch.The slip speed,the torque and the friction of the clutch are discussed in detail shifting performance such as wiping power,duty cycle,clutch pressure and flow.The numerical results show that the mathematical model considering damping force and hydrodynamic force can meet the requirements of heavy-duty automatic transmission for the performance analysis and optimization of the electro-hydraulic actuator;compared with the sequential quadratic programming algorithm,the artificial bee colony algorithm can minimize the clutch pressure response time.Compared with the original parameters,the optimized design has a great improvement in the fast response and precise control of shift.Secondly,the proposed robust control strategy,compared with the proportional integral differential controller,proves that the control strategy has good tracking performance for the shift control of heavy-duty automatic transmission,and can effectively improve the shift quality,thus reducing fuel consumption.