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
In-wheel motor-drive electric vehicles have the advantage of independently controllable wheel torque and the disadvantages of unsprung mass rise and power restriction.To address the disadvantages,a centralized layout ...In-wheel motor-drive electric vehicles have the advantage of independently controllable wheel torque and the disadvantages of unsprung mass rise and power restriction.To address the disadvantages,a centralized layout electric torque vectoring drive-axle system(E-TVDS)with dual motors is proposed,which can realize arbitrary distribution of driving torque between the left and right wheels.First,the speed and torque distribution principle of E-TVDS based on velocity diagram are analyzed,and a virtual prototype of the whole vehicle with basic gear ratio relation model of the E-TVDS is built for simulation to verify the theoretical results and the basic effect of E-TVDS on the steering performance of the vehicle.Second,the charac-teristics of 36 types of the novel E-TVDS topology structure are compared and analyzed,and the optimal structure scheme is selected.Third,the accurate multiple degrees of freedom dynamic model for the optimal structure is established by using the bond graph method,and its dynamic response characteristics are analyzed.The results show that the vehicle equipped with the proposed E-TVDS can distribute the driving torque with the almost identical amount but opposite sign between the left and right wheels in any direction,and varying amount according to different chassis dynamics control requirements,and the torque response performance is great with little delay and overshoot.The function and dynamic response of the proposed E-TVDS show that it has potential application value for various performance improvements of electric vehicles.展开更多
The principle of improving the torque amplification factor of E-TVDs with six elements is illustrated in this paper.A velocity diagram is used to study speed and torque relationships.The results reveal that the torque...The principle of improving the torque amplification factor of E-TVDs with six elements is illustrated in this paper.A velocity diagram is used to study speed and torque relationships.The results reveal that the torque amplification factor is the linear combination of the ratio of the differentials of the four elements and the ratio of planetary gear units,and its maximum value is easily more than 10.The E-TVDs with six elements are classified into three types,and there are six different configurations for each type.The torque amplification factor and the speed of interconnection between two planetary gear units are employed to evaluate the different characteristics of each E-TVD with six elements.The feasible configurations of a differential with four elements are also presented by the analysis of velocity level and planarity.This paper helps to further the understanding of the complex interconnection of the planetary gear units in E-TVDs with six elements and the differences of their characteristics.展开更多
To enhance the controllability of stratosphere airship,a vectored electric propulsion system is used.By using the Lagrangian method,a kinetic model of the vectored electric propulsion system is established and validat...To enhance the controllability of stratosphere airship,a vectored electric propulsion system is used.By using the Lagrangian method,a kinetic model of the vectored electric propulsion system is established and validated through ground tests.The fake gyroscopic torque is first proposed,which the vector mechanism should overcome besides the inertial torque and the gravitational torque.The fake gyroscopic torque is caused by the difference between inertial moments about two principal inertial axes of the propeller in the rotating plane,appears only when the propeller is rotating and is proportional with the rotation speed.It is a sinusoidal pulse,with a frequency that is twice of the rotation speed.Considering the fake gyroscope torque pulse and aerodynamic efficiency,three blade propeller is recommended for the vectored propulsion system used for stratosphere airship.展开更多
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This work is funded by the National Natural Science Foundation of China under Grant 51875235the Automobile Environmental Protection Innovation Leading Plan of FAW Volkswagen and China Environmental Protection Foundation,as well as in part by the Fundamental Research Funds for Central Universities of China under Grant 2020-JCXK-24.
文摘In-wheel motor-drive electric vehicles have the advantage of independently controllable wheel torque and the disadvantages of unsprung mass rise and power restriction.To address the disadvantages,a centralized layout electric torque vectoring drive-axle system(E-TVDS)with dual motors is proposed,which can realize arbitrary distribution of driving torque between the left and right wheels.First,the speed and torque distribution principle of E-TVDS based on velocity diagram are analyzed,and a virtual prototype of the whole vehicle with basic gear ratio relation model of the E-TVDS is built for simulation to verify the theoretical results and the basic effect of E-TVDS on the steering performance of the vehicle.Second,the charac-teristics of 36 types of the novel E-TVDS topology structure are compared and analyzed,and the optimal structure scheme is selected.Third,the accurate multiple degrees of freedom dynamic model for the optimal structure is established by using the bond graph method,and its dynamic response characteristics are analyzed.The results show that the vehicle equipped with the proposed E-TVDS can distribute the driving torque with the almost identical amount but opposite sign between the left and right wheels in any direction,and varying amount according to different chassis dynamics control requirements,and the torque response performance is great with little delay and overshoot.The function and dynamic response of the proposed E-TVDS show that it has potential application value for various performance improvements of electric vehicles.
基金Natural Science Foundation of Jiangsu Province(BK20160223)。
文摘The principle of improving the torque amplification factor of E-TVDs with six elements is illustrated in this paper.A velocity diagram is used to study speed and torque relationships.The results reveal that the torque amplification factor is the linear combination of the ratio of the differentials of the four elements and the ratio of planetary gear units,and its maximum value is easily more than 10.The E-TVDs with six elements are classified into three types,and there are six different configurations for each type.The torque amplification factor and the speed of interconnection between two planetary gear units are employed to evaluate the different characteristics of each E-TVD with six elements.The feasible configurations of a differential with four elements are also presented by the analysis of velocity level and planarity.This paper helps to further the understanding of the complex interconnection of the planetary gear units in E-TVDs with six elements and the differences of their characteristics.
文摘To enhance the controllability of stratosphere airship,a vectored electric propulsion system is used.By using the Lagrangian method,a kinetic model of the vectored electric propulsion system is established and validated through ground tests.The fake gyroscopic torque is first proposed,which the vector mechanism should overcome besides the inertial torque and the gravitational torque.The fake gyroscopic torque is caused by the difference between inertial moments about two principal inertial axes of the propeller in the rotating plane,appears only when the propeller is rotating and is proportional with the rotation speed.It is a sinusoidal pulse,with a frequency that is twice of the rotation speed.Considering the fake gyroscope torque pulse and aerodynamic efficiency,three blade propeller is recommended for the vectored propulsion system used for stratosphere airship.
