In order to research stability of four-wheel independent driving (4WID) electric vehicle, a torque allocation method based on the tire longitudinal forces optimization distribution is adopted. There are two layers in ...In order to research stability of four-wheel independent driving (4WID) electric vehicle, a torque allocation method based on the tire longitudinal forces optimization distribution is adopted. There are two layers in the controller, which includes the upper layer and the lower layer. In the upper layer, according to the demand of the longitudinal force, PID controller is set up to calculate the additional yaw moment created by yaw rate and side-slip angle. In the lower layer, the additional yaw moment is distributed properly to each wheel limited by several constraints. Carsim is used to build up the vehicle model and MATLAB/Simulink is used to build up the control model and both of them are used to simulate jointly. The result of simulation shows that a torque allocation method based on the tire longitudinal forces optimization distribution can ensure the stability of the vehicle.展开更多
Although electric vehicle fully exhibits its comparative merits of energy conservation and environmental friendliness, further improvement of its traction energy efficiency lacks comprehensive investigations in the pa...Although electric vehicle fully exhibits its comparative merits of energy conservation and environmental friendliness, further improvement of its traction energy efficiency lacks comprehensive investigations in the past. In this paper, the effect of the torque vectoring on traction energy conservation during cornering for a rear-wheel-independent-drive electric vehicle is investigated.Firstly, turning resistance coefficient and energy conservation mechanism of torque vectoring are derived from the single track dynamic model. Next, an optimal torque vectoring control strategy based on genetic algorithm is proposed, with the consideration of the influence of the operation-point change of the in-wheel motors, to find out the best torque vectoring ratio offline. Finally,various simulation tests are conducted to validate the energy conservation effect after Simulink modelling. The results verify that though the optimization of the operating region of the motors is the main part for tractive energy conservation, the contribution of torque vectoring itself can reach up to 1.7% in some typical cases.展开更多
新能源汽车转向驱动桥半轴采用空心设计,与燃油汽车的结构形式有很大区别,针对电动汽车转向驱动桥空心半轴的最大等效应力与设计变量呈隐式复杂非线性关系的可靠度分析难题,文中通过将Kriging模型与蒙特卡洛(Monte Carlo Simulation,MCS...新能源汽车转向驱动桥半轴采用空心设计,与燃油汽车的结构形式有很大区别,针对电动汽车转向驱动桥空心半轴的最大等效应力与设计变量呈隐式复杂非线性关系的可靠度分析难题,文中通过将Kriging模型与蒙特卡洛(Monte Carlo Simulation,MCS)法相结合,提出了基于AK-MCS(Active Learning Kriging-Monte Carlo Simulation)法的新能源电动汽车转向驱动桥空心半轴可靠度分析方法。首先,采用Kriging代理模型构建新能源电动汽车转向驱动桥空心半轴的最大等效应力的初始代理模型;其次,通过Kriging提供的学习函数和收敛准则逐步增加样本点,从而对初始最大等效应力的Kriging模型进行更新;最后,对更新后的Kriging代理模型计算新能源电动汽车转向驱动桥空心半轴的可靠度。结果表明:与MCS方法相比,基于AK-MCS方法的可靠度分析在时间上缩短2000余倍;与Kriging+MCS方法相比,基于AK-MCS方法的可靠度分析误差减小了50%。由此验证了基于AK-MCS方法空心半轴可靠度分析的高效性和准确性,为电动汽车转向驱动桥空心半轴可靠性的研究提供了理论依据,具有一定的工程意义。展开更多
Improving the energy efficiency of an electric vehicle(EV) is an effective approach to extend its driving range. This paper proposes an integrated energy-oriented lateral stability controller(IESC) for a four-wheel in...Improving the energy efficiency of an electric vehicle(EV) is an effective approach to extend its driving range. This paper proposes an integrated energy-oriented lateral stability controller(IESC) for a four-wheel independent-drive EV(4 WID-EV) to optimize its energy consumption while maintaining vehicular stability during cornering. The IESC is a hierarchical controller with two levels. The high-level decision-making controller determines the virtual control inputs, i.e., the desired additional yaw moment and total wheel torque, while the low-level controller allocates the motor torques according to the virtual control inputs.In the high-level controller, the desired additional yaw moment is first calculated using a linear quadratic regulator(LQR) to minimize the control expenditure. Meanwhile, a stability weighting factor(SWF) based on phase plane analysis is proposed to adjust the additional yaw moment, which can reduce the additional energy consumption caused by the mismatch between the reference model and the actual vehicle. In addition to the yaw moment, the desired total wheel torque is calculated using a proportional-integral(PI) controller to track the desired longitudinal velocity. In the low-level controller, a multi-objective convex-optimization problem is established to optimize the motor torque by minimizing the energy consumption and considering the tire-road frictional limit and motor saturation. A globally optimal solution is obtained by using an active-set method. Finally,double-lane change(DLC) simulations are conducted using Car Sim and MATLAB/Simulink. The simulation results demonstrate that the proposed controller achieves great lateral stability control performance and reduces the energy consumption by5.23% and 2.95% compared with the rule-based control strategy for high-and low-friction DLC maneuvers, respectively.展开更多
文摘In order to research stability of four-wheel independent driving (4WID) electric vehicle, a torque allocation method based on the tire longitudinal forces optimization distribution is adopted. There are two layers in the controller, which includes the upper layer and the lower layer. In the upper layer, according to the demand of the longitudinal force, PID controller is set up to calculate the additional yaw moment created by yaw rate and side-slip angle. In the lower layer, the additional yaw moment is distributed properly to each wheel limited by several constraints. Carsim is used to build up the vehicle model and MATLAB/Simulink is used to build up the control model and both of them are used to simulate jointly. The result of simulation shows that a torque allocation method based on the tire longitudinal forces optimization distribution can ensure the stability of the vehicle.
基金supported by the National Natural Science Foundation of China(Grant No.51205153)the Natural Science Foundation of Jilin Province(Grant No.20140101072JC)the 2018"13th Five-Year"Scientific Research Planning Project of the Education Department of Jilin Province as well as the 2018 Science and Technology Development Plan of Jilin Province-International Science and Technology Cooperation Project(Grant No.20180414011GH)
文摘Although electric vehicle fully exhibits its comparative merits of energy conservation and environmental friendliness, further improvement of its traction energy efficiency lacks comprehensive investigations in the past. In this paper, the effect of the torque vectoring on traction energy conservation during cornering for a rear-wheel-independent-drive electric vehicle is investigated.Firstly, turning resistance coefficient and energy conservation mechanism of torque vectoring are derived from the single track dynamic model. Next, an optimal torque vectoring control strategy based on genetic algorithm is proposed, with the consideration of the influence of the operation-point change of the in-wheel motors, to find out the best torque vectoring ratio offline. Finally,various simulation tests are conducted to validate the energy conservation effect after Simulink modelling. The results verify that though the optimization of the operating region of the motors is the main part for tractive energy conservation, the contribution of torque vectoring itself can reach up to 1.7% in some typical cases.
文摘新能源汽车转向驱动桥半轴采用空心设计,与燃油汽车的结构形式有很大区别,针对电动汽车转向驱动桥空心半轴的最大等效应力与设计变量呈隐式复杂非线性关系的可靠度分析难题,文中通过将Kriging模型与蒙特卡洛(Monte Carlo Simulation,MCS)法相结合,提出了基于AK-MCS(Active Learning Kriging-Monte Carlo Simulation)法的新能源电动汽车转向驱动桥空心半轴可靠度分析方法。首先,采用Kriging代理模型构建新能源电动汽车转向驱动桥空心半轴的最大等效应力的初始代理模型;其次,通过Kriging提供的学习函数和收敛准则逐步增加样本点,从而对初始最大等效应力的Kriging模型进行更新;最后,对更新后的Kriging代理模型计算新能源电动汽车转向驱动桥空心半轴的可靠度。结果表明:与MCS方法相比,基于AK-MCS方法的可靠度分析在时间上缩短2000余倍;与Kriging+MCS方法相比,基于AK-MCS方法的可靠度分析误差减小了50%。由此验证了基于AK-MCS方法空心半轴可靠度分析的高效性和准确性,为电动汽车转向驱动桥空心半轴可靠性的研究提供了理论依据,具有一定的工程意义。
基金supported in part by the National Natural Science Foundation of China(Grant Nos.51675281,and 51805081)the National Science and Technology Major Project of China(Grant No.2018ZX04024001)+2 种基金the Fundamental Research Funds for the Central Universities(Grant Nos.30918011101,and 309181B8809)and the Graduate Student Innovation Project of Jiangsu Province,China(Grant No.KYLX15_0341)the Chinese Scholarship Council for providing a scholarship(Grant No.201506840033)
文摘Improving the energy efficiency of an electric vehicle(EV) is an effective approach to extend its driving range. This paper proposes an integrated energy-oriented lateral stability controller(IESC) for a four-wheel independent-drive EV(4 WID-EV) to optimize its energy consumption while maintaining vehicular stability during cornering. The IESC is a hierarchical controller with two levels. The high-level decision-making controller determines the virtual control inputs, i.e., the desired additional yaw moment and total wheel torque, while the low-level controller allocates the motor torques according to the virtual control inputs.In the high-level controller, the desired additional yaw moment is first calculated using a linear quadratic regulator(LQR) to minimize the control expenditure. Meanwhile, a stability weighting factor(SWF) based on phase plane analysis is proposed to adjust the additional yaw moment, which can reduce the additional energy consumption caused by the mismatch between the reference model and the actual vehicle. In addition to the yaw moment, the desired total wheel torque is calculated using a proportional-integral(PI) controller to track the desired longitudinal velocity. In the low-level controller, a multi-objective convex-optimization problem is established to optimize the motor torque by minimizing the energy consumption and considering the tire-road frictional limit and motor saturation. A globally optimal solution is obtained by using an active-set method. Finally,double-lane change(DLC) simulations are conducted using Car Sim and MATLAB/Simulink. The simulation results demonstrate that the proposed controller achieves great lateral stability control performance and reduces the energy consumption by5.23% and 2.95% compared with the rule-based control strategy for high-and low-friction DLC maneuvers, respectively.
