Study On The Optimization Of Driving Control Strategy For Pure Electric Urban Bus

In recent years electric urban bus has become the focus of new energy vehicles, and large-scale promotion has been achieved due to the promotion of national policies. However, some objective factors such as shortage of specific energy restrict the development, therefore, it is practical to study how to reduce the energy consumption and increase the mileage of the vehicle. In order to improve the economy of bus, from the driver command decision-making level as well as the distribution of the drive system are studied, and achieve the purpose of reducing the energy consumption by optimizing control strategy. In order to improve the comfort of bus, the goal of easing the impact of the vehicle is reached by optimizing the torque response in research on response level of the electric drive system. The main research contents of this paper are as follows:(1) The establishment of mathematical model of Electric Urban Bus. The characteristics of bus drive system are analyzed, and the coaxial series dual motor system is focused in this paper by establishing the mathematical model of the driving system. The economic model of the electric city bus is established as simulation platform for the follow-up study of driver’s decision-making and control allocation of drive system. The physical model of the train system is built by SimDriveline to provide simulation and experiment platform for the control of electric drive system.(2) Study on optimization control of driver’s decision. By collecting driving behavior information of typical bus route, and focus on the influence of driver information on the energy consumption of the city bus, the factors that affect the vehicle energy consumption, such as the speed, acceleration and the standard deviation of the driver are obtained, and the strategy of the optimal control of the driver’s decision is proposed.(3) Optimization of energy distribution in drive system. By analysis of the characters of the structure of electric bus driver system and motor working principle,optimization of the energy allocation of drive system is proposed. Apply the control strategy based on dynamic programming to bus economic model,and energy consumption of the system with different control strategies is compared. The simulation results show that the energy allocation method based on Dynamic Programming can reduce energy consumption of the system and improve the overall efficiency of the system, by changing the motor operating point.(4) Study on suppression of vibration in transmission system. By analysis of the influence of torque mutation on shock and vibration of driveline,the issue of optimal control for vibration of driveline is proposed. Optimal control rate is obtained by solving the problem with MPC,and study on simulation of control effect with transmission system model,it turns out that MPC can reduce the vibration and impact of transmission effectively without changing the dynamic performance of passenger vehicle.(5) Study on control strategy with bench test and real vehicle experiment. Double motor drive system test bench was built with rapid control prototype based on MicroAutoBox, to verify the effectiveness of the energy allocation control strategy and the vibration suppression strategy by experiment on bench. The development of vehicle controller has been completed and driving system is equipped in real vehicle,so that experiment on real vehicle with control strategy is conducted. Experimental results shows that, driver decision optimization control and drive system energy allocation control can improve vehicle economy; and the torque control strategy of the driving system can reduce the vibration impact of the transmission system, so that the theory previously proposed has been basically verified.