Study On The Quality Optimizing Of Shifting Process Control Of Automatic Transmission For Mine-vehicle

The shifting quality of Automatic Transmission(AT)is the key to its engineering promotion and application,and it is the main factor affecting the life of the transmission system,fuel efficiency,driving comfort,and road adaptation.Based on the project "Design and Optimization of 6+2 Speed Automatic Transmission and Controller",this paper carries out research on the optimization of shifting quality for mine-vehicle by constructing a dynamic model of the transmission system,optimizing the oil pressure trajectory of the clutch,tracking the relative speed trajectory of the clutch,and carrying out a multi-objective optimal control simulation experiment of double-transition shifting.The purpose of this research is to reduce the jerk of shifting to protect the transmission system,reduce the sliding friction loss of shifting to improve the life of the clutch and optimize the shifting timing to improve driving comfort.In order to obtain the dynamic simulation model of the AT shifting process,this paper combines the Lagrange-method and the Stribeck friction model to carry out the dynamic modeling of the power input module,the planetary gear train module,the electro-hydraulic control system module,and the power output module in the transmission system of the mining vehicle.And then,combined with the development of smart mining technology,the traditional two-parameter economic shift strategy is corrected based on vehicle load and road slope.The dynamic programming optimization algorithm is used to extract the best economical shift strategy under known working conditions to reduce fuel consumption and the number of shifts.The control equations of the rigid shaft torque changing with oil pressure during the single-transition upshifting in the low gear phase,the torque phase,the inertia phase,and the high gear phase are deduced,and the mathematical expressions of the jerk and sliding friction loss of each phase are obtained.A linearquadratic optimal control regulator is used to achieve the optimum control pressure of clutches,where shifting jerk and clutch friction loss are chosen as a quadratic performance index function.Besides,a detailed solution of the linear-quadratic problem with disturbance matrix in the state equations is provided.The data-driven predictive control method is used to track and control the relative rotational speed of the clutch driving plate and the driven plate in AT shifting.In the inertia phase,the throttle opening and the current of the shift solenoid valve are used as input data,and the relative speed difference between the driving and driven plates of the oncoming clutch is used as output data.After the reference trajectory of the relative speed difference of the clutch is established,the error between the predicted value and the reference value is analyzed.Taking the change rate of the control variable and the inherent mechanical system as constraints,the trajectory tracking solution problem is transformed into a quadratic programming problem with constraints.In the process of optimizing and solving the constructed objective function,an improved particle swarm optimization algorithm is used to optimize the objective function.The off-line simulation and hardware-in-the-loop simulation experiments show that the method can make the relative speed difference of the clutch quickly track the reference trajectory.The dynamic analysis of the two groups of clutches in the double-transition shifting process is carried out.By adjusting the lap time of one group of clutches relative to the other group,five control modes are obtained.Taking the shifting jerk,clutch friction loss and shifting time as multi-objectives,the genetic algorithm is used to optimize the double-transition shifting.The simulation experiments and Pareto optimal analysis of the five control methods are carried out respectively.Through the simulation analysis,the reasonable two groups of clutch overlap mode can be obtained.Through the above research,the thesis builds the dynamic simulation model of the vehicle system,obtains the two-parameter economical shifting law based on DP optimization and the optimized curve of the shifting oil pressure control,realizes the accurate control of the speed tracking of the shifting clutch and finds out the optimal connection and coordination mode of double-transition shifting for multiple clutches.