Path following refers to traveling along the desired path with automatic steering control,which is a crucial technology for automatic driving vehicles.Roads in private areas are highly irregular,resulting in a large c...Path following refers to traveling along the desired path with automatic steering control,which is a crucial technology for automatic driving vehicles.Roads in private areas are highly irregular,resulting in a large curvature variation,which reduces the control accuracy of the path following.A curvature adaptive control(CAC)based path-following method was proposed to solve the problem mentioned above.Specifically,CAC takes advantage of the complementary characteristics in response to the path curvature fluctuation of pure pursuit and front-wheel feedback and by combining the two methods further enhances the immunity of the control accuracy in response to a curvature fluctuation.With CAC,the quantitative indices of the path curvature fluctuation and control accuracy were constructed.The model between the path curvature fluctuation and a dynamic parameter was identified using the quantitative index of the control accuracy as the optimization target.The experimental results of a real vehicle indicate that the control accuracy of path following is further enhanced by its immunity in response to curvature fluctuation improved by the CAC.In addition,CAC is easy to deploy and requires low demand for hardware resources.展开更多
An instantaneous emission model was developed to model and predict the real driving emissions of the low-speed vehicles. The emission database used in the model was measured by using portable emission measurement syst...An instantaneous emission model was developed to model and predict the real driving emissions of the low-speed vehicles. The emission database used in the model was measured by using portable emission measurement system （PEMS） under actual traffic conditions in the rural area, and the characteristics of the emission data were determined in relation to the driving kinematics （speed and acceleration） of the low-speed vehicle. The input of the emission model is driving cycle, and the model requires instantaneous vehicle speed and acceleration levels as input variables and uses them to interpolate the pollutant emission rate maps to calculate the transient pollutant emission rates, which will be accumulated to calculate the total emissions released during the whole driving cycle. And the vehicle fuel consumption was determined through the carbon balance method. The model predicted the emissions and fuel consumption of an in-use low-speed vehicle type model, which agreed well with the measured data.展开更多
Aim Toshorten integral design period of electric vehicles Methods The electric vehicle simulation program(EVSP), a modular user-friendly program which is written in Borland C++ OWL for Windows was developed. Results ...Aim Toshorten integral design period of electric vehicles Methods The electric vehicle simulation program(EVSP), a modular user-friendly program which is written in Borland C++ OWL for Windows was developed. Results EVSP allows simulating the dynamic and the economy performance of electric vehicles.EVSP provides many kinds of data input module,a large components library of electric vehicles and several kinds of speed cycle with these library,it is easily to develop a new concept of different drive trains or even to compare or improve the existing electric vehicles. The paper simulated the performance of YW6120DD Electric Bus, and analyzed the test results comparing with simulation results Conclusion The simulation results indicate that the EVSP may contribute to the developments of electric vehicles in general and the definition of the optimal match management in the drive train in particular.展开更多
For a distributed drive electric vehicle(DDEV)driven by four in-wheel motors,advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently,quickly and precisely.And dir...For a distributed drive electric vehicle(DDEV)driven by four in-wheel motors,advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently,quickly and precisely.And direct yaw-moment control(DYC)has been widely studied and applied to vehicle stability control.Good vehicle handling performance:quick yaw rate transient response,small overshoot,high steady yaw rate gain,etc,is required by drivers under normal conditions,which is less concerned,however.Based on the hierarchical control methodology,a novel control system using direct yaw moment control for improving handling performance of a distributed drive electric vehicle especially under normal driving conditions has been proposed.The upper-loop control system consists of two parts:a state feedback controller,which aims to realize the ideal transient response of yaw rate,with a vehicle sideslip angle observer;and a steering wheel angle feedforward controller designed to achieve a desired yaw rate steady gain.Under the restriction of the effect of poles and zeros in the closed-loop transfer function on the system response and the capacity of in-wheel motors,the integrated time and absolute error(ITAE)function is utilized as the cost function in the optimal control to calculate the ideal eigen frequency and damper coefficient of the system and obtain optimal feedback matrix and feedforward matrix.Simulations and experiments with a DDEV under multiple maneuvers are carried out and show the effectiveness of the proposed method:yaw rate rising time is reduced,steady yaw rate gain is increased,vehicle steering characteristic is close to neutral steer and drivers burdens are also reduced.The control system improves vehicle handling performance under normal conditions in both transient and steady response.State feedback control instead of model following control is introduced in the control system so that the sense of control intervention to drivers is relieved.展开更多
In this paper,a kind of lateral stability control strategy is put forward about the four wheel independent drive electric vehicle.The design of control system adopts hierarchical structure.Unlike the previous control ...In this paper,a kind of lateral stability control strategy is put forward about the four wheel independent drive electric vehicle.The design of control system adopts hierarchical structure.Unlike the previous control strategy,this paper introduces a method which is the combination of sliding mode control and optimal allocation algorithm.According to the driver’s operation commands(steering angle and speed),the steady state responses of the sideslip angle and yaw rate are obtained.Based on this,the reference model is built.Upper controller adopts the sliding mode control principle to obtain the desired yawing moment demand.Lower controller is designed to satisfy the desired yawing moment demand by optimal allocation of the tire longitudinal forces.Firstly,the optimization goal is built to minimize the actuator cost.Secondly,the weighted least-square method is used to design the tire longitudinal forces optimization distribution strategy under the constraint conditions of actuator and the friction oval.Beyond that,when the optimal allocation algorithm is not applied,a method of axial load ratio distribution is adopted.Finally,Car Sim associated with Simulink simulation experiments are designed under the conditions of different velocities and different pavements.The simulation results show that the control strategy designed in this paper has a good following effect comparing with the reference model and the sideslip angle is controlled within a small rang at the same time.Beyond that,based on the optimal distribution mode,the electromagnetic torque phase of each wheel can follow the trend of the vertical force of the tire,which shows the effectiveness of the optimal distribution algorithm.展开更多
A computer model for the performance simulation of vehicles equipped with traction drive continuously variable transmission （CVT） is presented. The model integrates the traction drive CVT subsystem into an existing ...A computer model for the performance simulation of vehicles equipped with traction drive continuously variable transmission （CVT） is presented. The model integrates the traction drive CVT subsystem into an existing overall vehicle system. The characteristics of engine output torque are formulated using neural networks, and torque converter is modeled using lookup tables. Component inputs and outputs are coupled in the dynamic equations and interfaces in the powertrain system. The model simulation can provide evaluation of vehicle performance in drivability, fuel economy and emission levels for various drive ranges prior to the prototyping of the vehicle. As a design tool, the model assists engineers in understanding the effect ofpowertrain components on vehicle performance and making decisions in the selection of key design parameters. The model is implemented in the MATLAB/Simulink environment. The performance simulation of a test vehicle is included as a numerical example to illustrate the effectiveness of the model.展开更多
Accurate estimation of sideslip angle and vehicle velocity is crucial for effective control of distributed drive electric vehicles.However,as these states are not directly measured,Kalman-based approaches utilizing in...Accurate estimation of sideslip angle and vehicle velocity is crucial for effective control of distributed drive electric vehicles.However,as these states are not directly measured,Kalman-based approaches utilizing in-vehicle sensors have been developed to estimate them.Unfortunately,existing methods tend to ignore the impact of data loss on estimation performance.Furthermore,the process noise,which changes dynamically due to varying driving conditions,is not adequately considered.In response to these constraints,we propose a novel method called the fuzzy adaptive fault-tolerant extended Kalman filter(FAFTEKF).Initially,a fault-tolerant EKF is devised to handle missing measurements.Additionally,a fuzzy logic system that dynamically updates the process noise matrix,is built to improve estimation accuracy under different driving conditions.Extensive experimental results validate the superiority of the FAFTEKF over the traditional EKF across various scenarios with different degrees of data loss.展开更多
The aim of this paper is to present a new topology of a DC-DC power converter for conditioning the current and voltages behaviors of embarked energy sources used in electrical vehicles. The fuel cells in conjunction w...The aim of this paper is to present a new topology of a DC-DC power converter for conditioning the current and voltages behaviors of embarked energy sources used in electrical vehicles. The fuel cells in conjunction with ultra-capacitors have been chosen as the power supply. The originality of the proposed converter is to use a variable voltage of the DC bus of the vehicle. The goal is to allow a better energy management of the embedded sources onboard the vehicle by improving its energy efficiency. After presenting and explaining the topology of the converter, some simulation and experiments results are shown to highlight its different operation modes.展开更多
Distributed drive electric vehicles(DDEVs)endow the ability to improve vehicle stability performance through direct yaw-moment control(DYC).However,the nonlinear characteristics pose a great challenge to vehicle dynam...Distributed drive electric vehicles(DDEVs)endow the ability to improve vehicle stability performance through direct yaw-moment control(DYC).However,the nonlinear characteristics pose a great challenge to vehicle dynamics control.For this purpose,this paper studies the DYC through the Takagi-Sugeno(T-S)fuzzy-based model predictive control to deal with the nonlinear challenge.First,a T-S fuzzy-based vehicle dynamics model is established to describe the time-varying tire cornering stiffness and vehicle speeds,and thus the uncertain parameters can be represented by the norm-bounded uncertainties.Then,a robust model predictive control(MPC)is developed to guarantee vehicle handling stability.A feasible solution can be obtained through a set of linear matrix inequalities(LMIs).Finally,the tests are conducted by the Carsim/Simulink joint platform to verify the proposed method.The comparative results show that the proposed strategy can effectively guarantee the vehicle’s lateral stability while handling the nonlinear challenge.展开更多
A new video-based measurement is proposed to collect and investigate traffic flow parameters. The output of the measurement is velocity-headway distance data pairs. Because density can be directly acquired by the reci...A new video-based measurement is proposed to collect and investigate traffic flow parameters. The output of the measurement is velocity-headway distance data pairs. Because density can be directly acquired by the reciprocal of headway distance, the data pairs have the advantage of better simultaneity than those from common detectors. By now, over 33 000 pairs of data have been collected from two road sections in the cities of Shanghai and Zhengzhou. Through analyzing the video files recording traffic movements on urban expressways, the following issues are studied：laws of vehicle velocity changing with headway distance, proportions of di0erent driving behaviors in the traffic system, and characteristics of traffic flow in snowy days. The results show that the real road traffic is very complex, and factors such as location and climate need to be taken into consideration in the formation of traffic flow models.展开更多
Lithium-ion batteries are commonly used in electric vehicles,mobile phones,and laptops.These batteries demonstrate several advantages,such as environmental friendliness,high energy density,and long life.However,batter...Lithium-ion batteries are commonly used in electric vehicles,mobile phones,and laptops.These batteries demonstrate several advantages,such as environmental friendliness,high energy density,and long life.However,battery overcharging and overdischarging may occur if the batteries are not monitored continuously.Overcharging causesfire and explosion casualties,and overdischar-ging causes a reduction in the battery capacity and life.In addition,the internal resistance of such batteries varies depending on their external temperature,elec-trolyte,cathode material,and other factors;the capacity of the batteries decreases with temperature.In this study,we develop a method for estimating the state of charge(SOC)using a neural network model that is best suited to the external tem-perature of such batteries based on their characteristics.During our simulation,we acquired data at temperatures of 25°C,30°C,35°C,and 40°C.Based on the tem-perature parameters,the voltage,current,and time parameters were obtained,and six cycles of the parameters based on the temperature were used for the experi-ment.Experimental data to verify the proposed method were obtained through a discharge experiment conducted using a vehicle driving simulator.The experi-mental data were provided as inputs to three types of neural network models:mul-tilayer neural network(MNN),long short-term memory(LSTM),and gated recurrent unit(GRU).The neural network models were trained and optimized for the specific temperatures measured during the experiment,and the SOC was estimated by selecting the most suitable model for each temperature.The experimental results revealed that the mean absolute errors of the MNN,LSTM,and GRU using the proposed method were 2.17%,2.19%,and 2.15%,respec-tively,which are better than those of the conventional method(4.47%,4.60%,and 4.40%).Finally,SOC estimation based on GRU using the proposed method was found to be 2.15%,which was the most accurate.展开更多
This paper presents the design method of hybrid drive system for the minibus with some limited conditions. The approach of design hybrid drive system is based on the dynamic modeling and simulation of the hybrid minib...This paper presents the design method of hybrid drive system for the minibus with some limited conditions. The approach of design hybrid drive system is based on the dynamic modeling and simulation of the hybrid minibus with planetary gear system. The main target of the design is to obtain the optimal design with the proper hybrid drive configuration and control for a given set of design constraints. In oder to meet the design target, it＇s necessary to adjust some parameters such as mechanical ratios and parameters of battery pack as well as control by simulation. During simulation the transient operating process can be studied in details with the dynamic model in Matlab/Simulink. The control strategy can be optimized by running the simulation and monitoring the operation of each components： the operating area of internal combustion engine （ICE）, fuel consumption （energy consumption）, the power distribution, the torque and rotary speed of ICE and motor, the operating efficiency of motor, the aheration of battery state of charge （SOC）, current and voltage.展开更多
The National Renewable Energy Laboratory and General Motors evaluated connectivity-enabled efficiency enhancements for the Chevrolet Volt.A high-level model was developed to predict vehicle fuel and electricity consum...The National Renewable Energy Laboratory and General Motors evaluated connectivity-enabled efficiency enhancements for the Chevrolet Volt.A high-level model was developed to predict vehicle fuel and electricity consumption based on driving characteristics and vehicle state inputs.These techniques were leveraged to optimize energy efficiency via green routing and intelligent control mode scheduling,which were evaluated using prospective driving routes between tens of thousands of real-world origin/destination pairs.The overall energy savings potential of green routing and intelligent mode scheduling was estimated at 5%and 3%,respectively.These represent substantial opportunities considering that they only require software adjustments to implement.展开更多
This paper proposes a novel model fusion approach to enhance predictive capabilities of vision and language models by strategically integrating object detection and large language models. We have named this multimodal...This paper proposes a novel model fusion approach to enhance predictive capabilities of vision and language models by strategically integrating object detection and large language models. We have named this multimodal integration approach as VOLTRON (Vision Object Linguistic Translation for Responsive Observation and Narration). VOLTRON is aimed at improving responses for self-driving vehicles in detecting small objects crossing roads and identifying merged or narrower lanes. The models are fused using a single layer to provide LLaMA2 (Large Language Model Meta AI) with object detection probabilities from YoloV8-n (You Only Look Once) translated into sentences. Experiments using specialized datasets showed accuracy improvements up to 88.16%. We provide a comprehensive exploration of the theoretical aspects that inform our model fusion approach, detailing the fundamental principles upon which it is built. Moreover, we elucidate the intricacies of the methodologies employed for merging these two disparate models, shedding light on the techniques and strategies used.展开更多
A yaw moment control strategy for four wheel independent drive electrics vehicle is proposed in this paper.The control strategy is a hierarchical architecture which containing a yaw motion generation layer and a longi...A yaw moment control strategy for four wheel independent drive electrics vehicle is proposed in this paper.The control strategy is a hierarchical architecture which containing a yaw motion generation layer and a longitudinal force distribution layer.The yaw motion generation layer consists of feedforward control and feedback control.Unlike previous strategy,in this paper,yaw rate is considered as the only control variable which is feasible to be detected in practice.The feedforward control is used to enhance overshoot in transient condition while the feedback control is to change vehicle steady state steering characteristic and extend its lateral limit.The longitudinal force distribution layer is designed based on vehicle wheel load transfer model.It makes each tire fully utilized its lateral force limits.Based on these two layers,a control model is built accordingly.Both steady state and transient state experiments are conducted in Carsim simulation associated with the built Simulink control model.The simulation results show that proposed control strategy can enhance vehicle handling performance in steady state and transient state.Experiments were conducted on an electric vehicle which evaluated the accuracy of the established model and the effect of the proposed yaw moment control strategy.展开更多
In order to solve the problem effectively that increasing car ownership relies on limited resources like oil and the resulting environmental pollution because of vehicle exhaust,＂New energy vehicles＂is not a new con...In order to solve the problem effectively that increasing car ownership relies on limited resources like oil and the resulting environmental pollution because of vehicle exhaust,＂New energy vehicles＂is not a new conception which is mentioned frequently and has been used in practical applications in our daily life. As a typical representative of the use of new energy vehicles,Prius,a kind of gas-electric hybrid cars which are made by Toyota is a very typical type in technique and application. Using Prius as an example,we will focus on its chemical reaction principle of electrical energy storage device and evaluation parameters,the structure of driving motors and gives the dqmodel of the electrical machine in dqcoordinates,the structure of dynamic coupling device,convertor assembly which including four kinds of convertor and its function,finally,introducing the working principles and characteristics of the system assembly in this paper.展开更多
The electric wheel has an advantage of independently,accurately,and promptly controlling torque in response.However,current distributed drive steering control strategies fail to fully leverage this capability.To fill ...The electric wheel has an advantage of independently,accurately,and promptly controlling torque in response.However,current distributed drive steering control strategies fail to fully leverage this capability.To fill this gap,this paper proposes a composite electronic moment power steering(EMPS)control strategy for multi-axle distributed drive vehicles,based on dynamic modeling and analysis.The proposed control strategy integrates EMPS with direct yaw moment control(DYC),enhancing steering flexibility and fault tolerance in the steering system at low speeds,while also ensuring vehicle stability at high velocities.It adopts a hierarchical control architecture,wherein the upper controller utilizes a nonlinear state observer for the joint estimation of multi-objective parameters,and the lower controller is responsible for the accurate tracking of the steering angle by EMPS,the yaw rate tracking by DYC,and the assignment of weights to the composite controller.By establishing and analyzing a detailed vehicle model and an electric drive steering axle dynamics model,a multi-dimensional feasible domain for EMPS is proposed,ensuring the safety and smoothness of steering maneuvers.The co-simulation of MATLAB/Simulink and TruckSim are conducted to verify the effectiveness of the composite control strategy.The EMPS controller is proved to have robust steering angle tracking performance,with the𝛽−̇𝛽trajectory consistently converging within the stability zone,maintaining a sufficient margin for tire longitudinal force under the composite steering control.Additionally,real vehicle testing confirms the effectiveness of EMPS and the redundancy tolerance of the steering functionality in distributed drive multi-axle vehicles equipped with EMPS.展开更多
In view of the requirements for high-performance epoxy resin(EP)enamelled wire insulating varnish in the rapidly developments of new energy vehicle drive motors,the problems of localised electric field concentration d...In view of the requirements for high-performance epoxy resin(EP)enamelled wire insulating varnish in the rapidly developments of new energy vehicle drive motors,the problems of localised electric field concentration due to the unevenness electric field distribution has to be solved.In this paper,to enhance the corona resistance,insulation,and mechanical properties of EP insulating varnish,the function dielectric gradient structure consists of hyperbranched polyester(HBP)inner layer and silane coupling agent(KH-550)modified graphene oxide(GO)nonlinear layer are proposed.The results show that the introduction of HBP not only adjusts the dielectric constant of the insulating varnish but also increases the breakdown field strength significantly,and with the increase of K-GO,the nonlinear conductivity of K-GO/EP insulating varnish becomes more prominent.Simulation results show that the highest field strength of the structural insulating varnish with different dielectric constant gradients is reduced to 16.7 kV/mm,and the field strength difference of the inner layer is reduced to 0.3 kV/mm,which further reduces the electric field aberration of the neighbouring interfaces as compared to the pure EP insulating varnish.This work provides a new strategy for constructing the dielectric gradient structure to meet the high corona resistance and insulating varnish requirements of high-voltage motor enamelled wire insulating varnish in actual industrial production.展开更多
In order to solve navigation problem of intelligent vehicle driving on urban roads and to achieve the navigation in intersection area, intersection transition area and section area. The relay navigation strategy and a...In order to solve navigation problem of intelligent vehicle driving on urban roads and to achieve the navigation in intersection area, intersection transition area and section area. The relay navigation strategy and algorithm can solve the navigation problem of intelligent vehicle driving in typical urban roads such as intersection area, intersection transition area and section area, realizing seamless handover among different typical areas. Bezier curve function model was introduced to different typical areas, which solved the self-adaption recognition problem in different typical areas and revised positional accuracy with the help of cloud computing positioning service. In order to explain the strategy implement, an instance based on the strategy was adopted. Instance analysis indicates that as for the navigation problem in intersection area, intersection transition area and section area, if the relay navigation strategy is utilized, the self-adaption recognition problem in different typical areas can be handled. Based on the relay navigation strategy, the drive of intelligent vehicle on urban roads can effectively solve the self-adaption recognition problem in different typical areas in urban and further solve driving problems of intelligent vehicle of the same category in urban roads.展开更多
基金the National Natural Science Foundation of China(No.U1764264)。
文摘Path following refers to traveling along the desired path with automatic steering control,which is a crucial technology for automatic driving vehicles.Roads in private areas are highly irregular,resulting in a large curvature variation,which reduces the control accuracy of the path following.A curvature adaptive control(CAC)based path-following method was proposed to solve the problem mentioned above.Specifically,CAC takes advantage of the complementary characteristics in response to the path curvature fluctuation of pure pursuit and front-wheel feedback and by combining the two methods further enhances the immunity of the control accuracy in response to a curvature fluctuation.With CAC,the quantitative indices of the path curvature fluctuation and control accuracy were constructed.The model between the path curvature fluctuation and a dynamic parameter was identified using the quantitative index of the control accuracy as the optimization target.The experimental results of a real vehicle indicate that the control accuracy of path following is further enhanced by its immunity in response to curvature fluctuation improved by the CAC.In addition,CAC is easy to deploy and requires low demand for hardware resources.
基金supported by the State Environmental Protection Department of Public Welfare Projects(201409013)the National Natural Science Foundation of China(No.51576016 and No.41275133)
文摘An instantaneous emission model was developed to model and predict the real driving emissions of the low-speed vehicles. The emission database used in the model was measured by using portable emission measurement system （PEMS） under actual traffic conditions in the rural area, and the characteristics of the emission data were determined in relation to the driving kinematics （speed and acceleration） of the low-speed vehicle. The input of the emission model is driving cycle, and the model requires instantaneous vehicle speed and acceleration levels as input variables and uses them to interpolate the pollutant emission rate maps to calculate the transient pollutant emission rates, which will be accumulated to calculate the total emissions released during the whole driving cycle. And the vehicle fuel consumption was determined through the carbon balance method. The model predicted the emissions and fuel consumption of an in-use low-speed vehicle type model, which agreed well with the measured data.
文摘Aim Toshorten integral design period of electric vehicles Methods The electric vehicle simulation program(EVSP), a modular user-friendly program which is written in Borland C++ OWL for Windows was developed. Results EVSP allows simulating the dynamic and the economy performance of electric vehicles.EVSP provides many kinds of data input module,a large components library of electric vehicles and several kinds of speed cycle with these library,it is easily to develop a new concept of different drive trains or even to compare or improve the existing electric vehicles. The paper simulated the performance of YW6120DD Electric Bus, and analyzed the test results comparing with simulation results Conclusion The simulation results indicate that the EVSP may contribute to the developments of electric vehicles in general and the definition of the optimal match management in the drive train in particular.
基金Supported by National Basic Research Program of China(973 Program,Grant No.2011CB711200)National Science and Technology Support Program of China(Grant No.2015BAG17B00)National Natural Science Foundation of China(Grant No.51475333)
文摘For a distributed drive electric vehicle(DDEV)driven by four in-wheel motors,advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently,quickly and precisely.And direct yaw-moment control(DYC)has been widely studied and applied to vehicle stability control.Good vehicle handling performance:quick yaw rate transient response,small overshoot,high steady yaw rate gain,etc,is required by drivers under normal conditions,which is less concerned,however.Based on the hierarchical control methodology,a novel control system using direct yaw moment control for improving handling performance of a distributed drive electric vehicle especially under normal driving conditions has been proposed.The upper-loop control system consists of two parts:a state feedback controller,which aims to realize the ideal transient response of yaw rate,with a vehicle sideslip angle observer;and a steering wheel angle feedforward controller designed to achieve a desired yaw rate steady gain.Under the restriction of the effect of poles and zeros in the closed-loop transfer function on the system response and the capacity of in-wheel motors,the integrated time and absolute error(ITAE)function is utilized as the cost function in the optimal control to calculate the ideal eigen frequency and damper coefficient of the system and obtain optimal feedback matrix and feedforward matrix.Simulations and experiments with a DDEV under multiple maneuvers are carried out and show the effectiveness of the proposed method:yaw rate rising time is reduced,steady yaw rate gain is increased,vehicle steering characteristic is close to neutral steer and drivers burdens are also reduced.The control system improves vehicle handling performance under normal conditions in both transient and steady response.State feedback control instead of model following control is introduced in the control system so that the sense of control intervention to drivers is relieved.
基金supported by the National Nature Science Foundation(U1664263)National Key R&D Program of China(2016YFB0101102)。
文摘In this paper,a kind of lateral stability control strategy is put forward about the four wheel independent drive electric vehicle.The design of control system adopts hierarchical structure.Unlike the previous control strategy,this paper introduces a method which is the combination of sliding mode control and optimal allocation algorithm.According to the driver’s operation commands(steering angle and speed),the steady state responses of the sideslip angle and yaw rate are obtained.Based on this,the reference model is built.Upper controller adopts the sliding mode control principle to obtain the desired yawing moment demand.Lower controller is designed to satisfy the desired yawing moment demand by optimal allocation of the tire longitudinal forces.Firstly,the optimization goal is built to minimize the actuator cost.Secondly,the weighted least-square method is used to design the tire longitudinal forces optimization distribution strategy under the constraint conditions of actuator and the friction oval.Beyond that,when the optimal allocation algorithm is not applied,a method of axial load ratio distribution is adopted.Finally,Car Sim associated with Simulink simulation experiments are designed under the conditions of different velocities and different pavements.The simulation results show that the control strategy designed in this paper has a good following effect comparing with the reference model and the sideslip angle is controlled within a small rang at the same time.Beyond that,based on the optimal distribution mode,the electromagnetic torque phase of each wheel can follow the trend of the vertical force of the tire,which shows the effectiveness of the optimal distribution algorithm.
基金This project is supported by University Research Program of Ford MotorCompany and Visiting Scholar Program of State Key Laboratory on Me-chanical Transmission of Chongqing University, China.
文摘A computer model for the performance simulation of vehicles equipped with traction drive continuously variable transmission （CVT） is presented. The model integrates the traction drive CVT subsystem into an existing overall vehicle system. The characteristics of engine output torque are formulated using neural networks, and torque converter is modeled using lookup tables. Component inputs and outputs are coupled in the dynamic equations and interfaces in the powertrain system. The model simulation can provide evaluation of vehicle performance in drivability, fuel economy and emission levels for various drive ranges prior to the prototyping of the vehicle. As a design tool, the model assists engineers in understanding the effect ofpowertrain components on vehicle performance and making decisions in the selection of key design parameters. The model is implemented in the MATLAB/Simulink environment. The performance simulation of a test vehicle is included as a numerical example to illustrate the effectiveness of the model.
基金Supported by National Natural Science Foundation of China(Grant No.52402482).
文摘Accurate estimation of sideslip angle and vehicle velocity is crucial for effective control of distributed drive electric vehicles.However,as these states are not directly measured,Kalman-based approaches utilizing in-vehicle sensors have been developed to estimate them.Unfortunately,existing methods tend to ignore the impact of data loss on estimation performance.Furthermore,the process noise,which changes dynamically due to varying driving conditions,is not adequately considered.In response to these constraints,we propose a novel method called the fuzzy adaptive fault-tolerant extended Kalman filter(FAFTEKF).Initially,a fault-tolerant EKF is devised to handle missing measurements.Additionally,a fuzzy logic system that dynamically updates the process noise matrix,is built to improve estimation accuracy under different driving conditions.Extensive experimental results validate the superiority of the FAFTEKF over the traditional EKF across various scenarios with different degrees of data loss.
文摘The aim of this paper is to present a new topology of a DC-DC power converter for conditioning the current and voltages behaviors of embarked energy sources used in electrical vehicles. The fuel cells in conjunction with ultra-capacitors have been chosen as the power supply. The originality of the proposed converter is to use a variable voltage of the DC bus of the vehicle. The goal is to allow a better energy management of the embedded sources onboard the vehicle by improving its energy efficiency. After presenting and explaining the topology of the converter, some simulation and experiments results are shown to highlight its different operation modes.
基金Supported by National Natural Science Foundation of China(Grant Nos.52402497,52025121 and 52002066)Young Scientists Project and General Project of Applied Basic Research in Yunnan Province(Grant Nos.202501AT070296,202401AU070196)+1 种基金The Key Laboratory of Modern Agricultural Engineering of Ordinary Colleges and Universities of Education Department of Autonomous Region(Grant No.TDNG2023108)Jiangsu Provincial Achievements Transformation Project(Grant No.BA2018023).
文摘Distributed drive electric vehicles(DDEVs)endow the ability to improve vehicle stability performance through direct yaw-moment control(DYC).However,the nonlinear characteristics pose a great challenge to vehicle dynamics control.For this purpose,this paper studies the DYC through the Takagi-Sugeno(T-S)fuzzy-based model predictive control to deal with the nonlinear challenge.First,a T-S fuzzy-based vehicle dynamics model is established to describe the time-varying tire cornering stiffness and vehicle speeds,and thus the uncertain parameters can be represented by the norm-bounded uncertainties.Then,a robust model predictive control(MPC)is developed to guarantee vehicle handling stability.A feasible solution can be obtained through a set of linear matrix inequalities(LMIs).Finally,the tests are conducted by the Carsim/Simulink joint platform to verify the proposed method.The comparative results show that the proposed strategy can effectively guarantee the vehicle’s lateral stability while handling the nonlinear challenge.
基金supported by the National Natural Science Foundation of China (10772050)
文摘A new video-based measurement is proposed to collect and investigate traffic flow parameters. The output of the measurement is velocity-headway distance data pairs. Because density can be directly acquired by the reciprocal of headway distance, the data pairs have the advantage of better simultaneity than those from common detectors. By now, over 33 000 pairs of data have been collected from two road sections in the cities of Shanghai and Zhengzhou. Through analyzing the video files recording traffic movements on urban expressways, the following issues are studied：laws of vehicle velocity changing with headway distance, proportions of di0erent driving behaviors in the traffic system, and characteristics of traffic flow in snowy days. The results show that the real road traffic is very complex, and factors such as location and climate need to be taken into consideration in the formation of traffic flow models.
基金supported by the BK21 FOUR project funded by the Ministry of Education,Korea(4199990113966).
文摘Lithium-ion batteries are commonly used in electric vehicles,mobile phones,and laptops.These batteries demonstrate several advantages,such as environmental friendliness,high energy density,and long life.However,battery overcharging and overdischarging may occur if the batteries are not monitored continuously.Overcharging causesfire and explosion casualties,and overdischar-ging causes a reduction in the battery capacity and life.In addition,the internal resistance of such batteries varies depending on their external temperature,elec-trolyte,cathode material,and other factors;the capacity of the batteries decreases with temperature.In this study,we develop a method for estimating the state of charge(SOC)using a neural network model that is best suited to the external tem-perature of such batteries based on their characteristics.During our simulation,we acquired data at temperatures of 25°C,30°C,35°C,and 40°C.Based on the tem-perature parameters,the voltage,current,and time parameters were obtained,and six cycles of the parameters based on the temperature were used for the experi-ment.Experimental data to verify the proposed method were obtained through a discharge experiment conducted using a vehicle driving simulator.The experi-mental data were provided as inputs to three types of neural network models:mul-tilayer neural network(MNN),long short-term memory(LSTM),and gated recurrent unit(GRU).The neural network models were trained and optimized for the specific temperatures measured during the experiment,and the SOC was estimated by selecting the most suitable model for each temperature.The experimental results revealed that the mean absolute errors of the MNN,LSTM,and GRU using the proposed method were 2.17%,2.19%,and 2.15%,respec-tively,which are better than those of the conventional method(4.47%,4.60%,and 4.40%).Finally,SOC estimation based on GRU using the proposed method was found to be 2.15%,which was the most accurate.
文摘This paper presents the design method of hybrid drive system for the minibus with some limited conditions. The approach of design hybrid drive system is based on the dynamic modeling and simulation of the hybrid minibus with planetary gear system. The main target of the design is to obtain the optimal design with the proper hybrid drive configuration and control for a given set of design constraints. In oder to meet the design target, it＇s necessary to adjust some parameters such as mechanical ratios and parameters of battery pack as well as control by simulation. During simulation the transient operating process can be studied in details with the dynamic model in Matlab/Simulink. The control strategy can be optimized by running the simulation and monitoring the operation of each components： the operating area of internal combustion engine （ICE）, fuel consumption （energy consumption）, the power distribution, the torque and rotary speed of ICE and motor, the operating efficiency of motor, the aheration of battery state of charge （SOC）, current and voltage.
文摘The National Renewable Energy Laboratory and General Motors evaluated connectivity-enabled efficiency enhancements for the Chevrolet Volt.A high-level model was developed to predict vehicle fuel and electricity consumption based on driving characteristics and vehicle state inputs.These techniques were leveraged to optimize energy efficiency via green routing and intelligent control mode scheduling,which were evaluated using prospective driving routes between tens of thousands of real-world origin/destination pairs.The overall energy savings potential of green routing and intelligent mode scheduling was estimated at 5%and 3%,respectively.These represent substantial opportunities considering that they only require software adjustments to implement.
文摘This paper proposes a novel model fusion approach to enhance predictive capabilities of vision and language models by strategically integrating object detection and large language models. We have named this multimodal integration approach as VOLTRON (Vision Object Linguistic Translation for Responsive Observation and Narration). VOLTRON is aimed at improving responses for self-driving vehicles in detecting small objects crossing roads and identifying merged or narrower lanes. The models are fused using a single layer to provide LLaMA2 (Large Language Model Meta AI) with object detection probabilities from YoloV8-n (You Only Look Once) translated into sentences. Experiments using specialized datasets showed accuracy improvements up to 88.16%. We provide a comprehensive exploration of the theoretical aspects that inform our model fusion approach, detailing the fundamental principles upon which it is built. Moreover, we elucidate the intricacies of the methodologies employed for merging these two disparate models, shedding light on the techniques and strategies used.
文摘A yaw moment control strategy for four wheel independent drive electrics vehicle is proposed in this paper.The control strategy is a hierarchical architecture which containing a yaw motion generation layer and a longitudinal force distribution layer.The yaw motion generation layer consists of feedforward control and feedback control.Unlike previous strategy,in this paper,yaw rate is considered as the only control variable which is feasible to be detected in practice.The feedforward control is used to enhance overshoot in transient condition while the feedback control is to change vehicle steady state steering characteristic and extend its lateral limit.The longitudinal force distribution layer is designed based on vehicle wheel load transfer model.It makes each tire fully utilized its lateral force limits.Based on these two layers,a control model is built accordingly.Both steady state and transient state experiments are conducted in Carsim simulation associated with the built Simulink control model.The simulation results show that proposed control strategy can enhance vehicle handling performance in steady state and transient state.Experiments were conducted on an electric vehicle which evaluated the accuracy of the established model and the effect of the proposed yaw moment control strategy.
基金supported by Natural Science Foundation of Henan Province(under Grant No.211B580001)Henan Province Key Project(under Grant No.122102210045)Henan Polytechnic University Doctoral Foundtion(under Grant No.B2010-12)
文摘In order to solve the problem effectively that increasing car ownership relies on limited resources like oil and the resulting environmental pollution because of vehicle exhaust,＂New energy vehicles＂is not a new conception which is mentioned frequently and has been used in practical applications in our daily life. As a typical representative of the use of new energy vehicles,Prius,a kind of gas-electric hybrid cars which are made by Toyota is a very typical type in technique and application. Using Prius as an example,we will focus on its chemical reaction principle of electrical energy storage device and evaluation parameters,the structure of driving motors and gives the dqmodel of the electrical machine in dqcoordinates,the structure of dynamic coupling device,convertor assembly which including four kinds of convertor and its function,finally,introducing the working principles and characteristics of the system assembly in this paper.
基金National Key R&D Program of China(2022YFE0100100 ,Nos.52002210)Young Elite Scientists Sponsorship Program by CAST(No.2021QNRC001)Tsinghua University postdoctoral program(Shuimu Tsinghua Scholar Program).
文摘The electric wheel has an advantage of independently,accurately,and promptly controlling torque in response.However,current distributed drive steering control strategies fail to fully leverage this capability.To fill this gap,this paper proposes a composite electronic moment power steering(EMPS)control strategy for multi-axle distributed drive vehicles,based on dynamic modeling and analysis.The proposed control strategy integrates EMPS with direct yaw moment control(DYC),enhancing steering flexibility and fault tolerance in the steering system at low speeds,while also ensuring vehicle stability at high velocities.It adopts a hierarchical control architecture,wherein the upper controller utilizes a nonlinear state observer for the joint estimation of multi-objective parameters,and the lower controller is responsible for the accurate tracking of the steering angle by EMPS,the yaw rate tracking by DYC,and the assignment of weights to the composite controller.By establishing and analyzing a detailed vehicle model and an electric drive steering axle dynamics model,a multi-dimensional feasible domain for EMPS is proposed,ensuring the safety and smoothness of steering maneuvers.The co-simulation of MATLAB/Simulink and TruckSim are conducted to verify the effectiveness of the composite control strategy.The EMPS controller is proved to have robust steering angle tracking performance,with the𝛽−̇𝛽trajectory consistently converging within the stability zone,maintaining a sufficient margin for tire longitudinal force under the composite steering control.Additionally,real vehicle testing confirms the effectiveness of EMPS and the redundancy tolerance of the steering functionality in distributed drive multi-axle vehicles equipped with EMPS.
基金The National Natural Science Foundation of China(Grant 52107014)China Postdoctoral Science Foundation(Grants 2022M710981 and 2023T160171)Shandong Provincial Natural Science Foundation(Grant ZR2022QE187).
文摘In view of the requirements for high-performance epoxy resin(EP)enamelled wire insulating varnish in the rapidly developments of new energy vehicle drive motors,the problems of localised electric field concentration due to the unevenness electric field distribution has to be solved.In this paper,to enhance the corona resistance,insulation,and mechanical properties of EP insulating varnish,the function dielectric gradient structure consists of hyperbranched polyester(HBP)inner layer and silane coupling agent(KH-550)modified graphene oxide(GO)nonlinear layer are proposed.The results show that the introduction of HBP not only adjusts the dielectric constant of the insulating varnish but also increases the breakdown field strength significantly,and with the increase of K-GO,the nonlinear conductivity of K-GO/EP insulating varnish becomes more prominent.Simulation results show that the highest field strength of the structural insulating varnish with different dielectric constant gradients is reduced to 16.7 kV/mm,and the field strength difference of the inner layer is reduced to 0.3 kV/mm,which further reduces the electric field aberration of the neighbouring interfaces as compared to the pure EP insulating varnish.This work provides a new strategy for constructing the dielectric gradient structure to meet the high corona resistance and insulating varnish requirements of high-voltage motor enamelled wire insulating varnish in actual industrial production.
基金supported by the National Natural Science Foundation of China (61035004, 61273213, 61300006, 61305055, 90920305, 61203366)
文摘In order to solve navigation problem of intelligent vehicle driving on urban roads and to achieve the navigation in intersection area, intersection transition area and section area. The relay navigation strategy and algorithm can solve the navigation problem of intelligent vehicle driving in typical urban roads such as intersection area, intersection transition area and section area, realizing seamless handover among different typical areas. Bezier curve function model was introduced to different typical areas, which solved the self-adaption recognition problem in different typical areas and revised positional accuracy with the help of cloud computing positioning service. In order to explain the strategy implement, an instance based on the strategy was adopted. Instance analysis indicates that as for the navigation problem in intersection area, intersection transition area and section area, if the relay navigation strategy is utilized, the self-adaption recognition problem in different typical areas can be handled. Based on the relay navigation strategy, the drive of intelligent vehicle on urban roads can effectively solve the self-adaption recognition problem in different typical areas in urban and further solve driving problems of intelligent vehicle of the same category in urban roads.
