Shift Schedule Optimization Of Heavy Off-road Vehicle Based On Dynamic Programming

In order to improve the performance of heavy off-road vehicle equipped with automated manual transmission(AMT)during travelling,the shift schedule is studied in order to improve the fuel economy.The powertrain of the vehicle is modeled and the operating characteristics of the AMT is analyzed.Shift sequence optimization with dynamic programming(DP)based on driving cycle is developed.The heavy off-road vehicle driving cycle is established by analyzing quantities of driving data.The optimization problem of optimal shift sequence of heavy off-road vehicle driving cycle is solved,and the result is used to design the DP shift schedule.The main study points are as follows:(1)Mathematic modelling of AMT powertrain;Analysis of vehicle dynamics and operating characteristics of automatic shift control system.(2)Develop the method of calculating the optimal shift sequence under specific driving cycle with dynamic programming.Define the power reserve as the evaluation index of driveability and multiparameter indicator function is established.Improve the Computation process of DP according to the characteristic of power interruption during gearshift operation of AMT.(3)Analyze vehicle test driving data,extract driving sample;Devide the samples into five sample space according to the test condition.Structure driving cycle for each sample space and then make up the heavy off-road vehicle driving cycle.(4)Calculate the optimal shift sequence of heavy off-road vehicle driving cycle with DP.Analyze the result by clustering analysis.Then design the DP shift schedule with cluster result.Simulation shows the DP shift schedule can meet the target of better fuel economy while dynamic performance is also satisfactory.