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
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
When a four in-wheel motors drive electric vehicle with a specific wheels mass is running on an uneven road and transient steering occurs in the meantime, the joint action of the large unsprung dynamic load and the ce...When a four in-wheel motors drive electric vehicle with a specific wheels mass is running on an uneven road and transient steering occurs in the meantime, the joint action of the large unsprung dynamic load and the centrifugal force may cause the vehicle to rollover. To avoid the above accident, a rollover prevention control method based on active distribution of the in-wheel motors driving torques is investigated. First, tile rollover evolution process of the four in-wheel motors drive electric vehicle under the described operating condition is analyzed. Next, a multiple degrees of freedom vehicle dynamics model including an uneven road tyre model is established, and the rollover warning threshold is determined according to the load transfer ratio. Then, the hypothesis of the effects of unsprung mass on the vehicle roll stability on a plat road and on an uneven road is verified respectively. Finally, a rollover prevention controller is designed based on the distribution of the four wheels driving torques with sliding mode control, and the control effect is verified by simulations. The conclusion shows that, once the wheels mass does not match road conditions, the large unsprung mass may play a detrimental role on the vehicle roll stability on an uneven road, which is different from the beneficial role of large unsprung mass on the vehicle roll stability on a plat road. With the aforementioned rollover prevention controller, the vehicle rollover, which is caused by the coupling effect between large unsprung dynamic load and suspension potential energy on an uneven road, can be avoided effectively.展开更多
介绍了一种四轮独立驱动与转向(Four-Wheel Independent Driving and Steering,4WIS-4WID)电动车辆的结构和原理,对其电子操纵系统进行了设计,在此基础上构建了一种基于CAN总线的车辆运动网络控制系统。该电动车辆具有全轮转向、前(后)...介绍了一种四轮独立驱动与转向(Four-Wheel Independent Driving and Steering,4WIS-4WID)电动车辆的结构和原理,对其电子操纵系统进行了设计,在此基础上构建了一种基于CAN总线的车辆运动网络控制系统。该电动车辆具有全轮转向、前(后)轮转向、平行移动、原地转向等多种转向模式,分别对这些运动转向模式进行运动学建模。在控制策略上提出了一种分布式"位置—速度"双环反馈控制策略,各车轮转向角同时调节,车轮运动动态跟踪性能良好,车辆满足实时运动学要求。最后通过实车试验验证了网络控制系统结构和控制策略的有效性。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.
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.
基金supported by the National Natural Science Foundation of China(Grant Nos.51405259&51775478)
文摘When a four in-wheel motors drive electric vehicle with a specific wheels mass is running on an uneven road and transient steering occurs in the meantime, the joint action of the large unsprung dynamic load and the centrifugal force may cause the vehicle to rollover. To avoid the above accident, a rollover prevention control method based on active distribution of the in-wheel motors driving torques is investigated. First, tile rollover evolution process of the four in-wheel motors drive electric vehicle under the described operating condition is analyzed. Next, a multiple degrees of freedom vehicle dynamics model including an uneven road tyre model is established, and the rollover warning threshold is determined according to the load transfer ratio. Then, the hypothesis of the effects of unsprung mass on the vehicle roll stability on a plat road and on an uneven road is verified respectively. Finally, a rollover prevention controller is designed based on the distribution of the four wheels driving torques with sliding mode control, and the control effect is verified by simulations. The conclusion shows that, once the wheels mass does not match road conditions, the large unsprung mass may play a detrimental role on the vehicle roll stability on an uneven road, which is different from the beneficial role of large unsprung mass on the vehicle roll stability on a plat road. With the aforementioned rollover prevention controller, the vehicle rollover, which is caused by the coupling effect between large unsprung dynamic load and suspension potential energy on an uneven road, can be avoided effectively.
文摘介绍了一种四轮独立驱动与转向(Four-Wheel Independent Driving and Steering,4WIS-4WID)电动车辆的结构和原理,对其电子操纵系统进行了设计,在此基础上构建了一种基于CAN总线的车辆运动网络控制系统。该电动车辆具有全轮转向、前(后)轮转向、平行移动、原地转向等多种转向模式,分别对这些运动转向模式进行运动学建模。在控制策略上提出了一种分布式"位置—速度"双环反馈控制策略,各车轮转向角同时调节,车轮运动动态跟踪性能良好,车辆满足实时运动学要求。最后通过实车试验验证了网络控制系统结构和控制策略的有效性。
