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2016-04-05
Technical Paper
2016-01-1671
Dejian Han, Zhen Yan, Feng Xiao, Shaokun Li MD
In the context of the global energy crisis and environmental degradation, electric vehicles (EVs) have been gaining a lot of focus and attention as they run clean and are environment friendly. The electric vehicle with in-wheel motors is a promising form of EV, which is driven by four in-wheel motors. Under this mode, the driving and brake torques of each of wheel can be controlled independently. Stability control of the vehicle requires the vehicle to travel along an ideal trajectory and remain the ideal state all the time. Direct yaw moment control (DYC) has a high ability to maintain the vehicle stability in critical situation. For four-wheel independently driven (4WD) electric vehicle with in-wheel motors (IWMs), direct DYC system can work more flexibly and efficiently than internal combustion engine vehicles, because the driving/braking torque of each wheel can be controlled accurately. In this paper, a hierarchical direct yaw moment controller is developed.
2016-04-05
Technical Paper
2016-01-0472
Lianhui Wang, Shuming Chen, Dengfeng Wang, Yang Jiang, Jing chen
With the development of modern transportation industry, noise pollution is becoming a serious problem. Thus how to reduce noise becomes a hot topic. The most commonly used method is the use of porous sound absorption materials. There are different ways to predict the sound absorption performance of the materials. One of them is genetic algorithm. It can intuitively find critical information that cannot be found in theory. Genetic algorithm is an excellent simulation method. It acquires the optimal solution by imitating the natural selection and genetic mechanism. Therefore, the solution is more close to the target solution after multiple optimizations. The purpose of the present study is to propose a novel approach applying the genetic algorithm to predict the porous materials' sound absorption properties. In this paper we use the foam as the porous material.
2016-04-05
Technical Paper
2016-01-1487
Zhenhai Gao, Chuzhao Li, Hongyu Hu, Chaoyang Chen, Hui Zhao, Helen YU
At the collision moment, a driver’s lower extremity will be in different braking stage, which leads to different posture of lower extremity with various muscle activations. These will affect the driver’s injury during collision but it was not fully investigated. In this study, a simulated collision scene was constructed and the posture and muscle activation of lower extremity at the collision moment were studied. 20 participants (10 male and 10 female) were recruited for the simulated collision test and muscle activation of 8 major muscles in both right and left legs were measured. Muscle activation of lower extremity in different postures was analyzed. It was found that the driver’s right leg was possible to be on the brake, in the air or even on the accelerator at the collision moment. The left leg was on the floor all along. Significant differences of right leg’s muscle activation were found between different postures.
2016-04-05
Technical Paper
2016-01-1203
Zhang Qiao, Weiwen Deng, Jian Wu
This paper describes a novel power management control strategy of battery and supercapacitor hybrid energy storage system for electric vehicle to improve system efficiency and battery lifetime. The battery lifetime may be dramatically impacted by frequent charge or discharge current resulted from the rapid variation of the load power demand. In the presented research, the high and low frequency power demand in the load is separated by a Haar wavelet transform algorithm to overcome the problem of battery overload work and associated degeneration in battery lifetime resulting from an ineffective distribution between battery and supercapacitor. The purpose of frequency distribution is that the supercapacitor is used to share high frequency power components of load power demand to smooth the power demand applied to battery. As a result, the low frequent power can be shared by battery. This control strategy can be specifically referred to as sole frequency control.
2016-04-05
Technical Paper
2016-01-1242
Zhang Qiao, Weiwen Deng, Jian Wu, Feng Ju, Jingshan Li
In this paper, the power management control strategy of battery and supercapacitor hybrid energy storage system is developed by introducing terrain information to optimize system efficiency and battery lifetime, which is affected largely by the rapid variation of load power demand resulted from not only kinds of driving cycles but also terrain variation. In this presented research, we aim at developing a power management control strategy considering the influence of the terrain information on system efficiency and battery lifetime. In order to avoid rapid changes of power demand and achieve high efficiency without degrading the mechanism performance, a Haar wavelet transform algorithm is proposed to decompose different frequencies components of the load power demand. The results demonstrate that the proposed algorithm is able to ensure the major portion of the low frequency components of power demand can be dealt with the battery.
2016-04-05
Technical Paper
2016-01-1296
Yuntao Cao, Dengfeng Wang, Tonghang Zhao, Xining Liu, Chao Li, Hangsheng Hou
The source of noise excitation is different between electric and conventional vehicles due to their distinctive power system architecture. This work focuses on an interior noise contribution analysis using a model established base on the noise path analysis principle. The obtained results show that the structural-borne noise from the road excitation acts as a major contributor to the overall interior noise level, and the structural-borne noise from the powertrain system contributes noticeably as well, whereas the contribution from the electric motor and tire is relatively insignificant.
2016-04-05
Technical Paper
2016-01-1307
Yuntao Cao, Dengfeng Wang, Tonghang Zhao, Xining Liu, Yulei He, Hangsheng Hou
A vehicle vibration issue emerged for a hybrid prototype in pure electric mode during low speed driving. This work explains the effort to identify the root course, and the work performed to resolve the issue. Firstly a motor test was performed with moderate acceleration by enforcing a constant torque load. All relevant information was simultaneously recorded, including the vehicle speed, motor rpm, motor voltage and current signals, the vibration of the motor structure and seat track, etc. Secondly analyses were carried out regarding vehicle vibration characteristics and mechanism. It was found that the torque fluctuation from the motor was the root course of the low speed vehicle vibration under pure electric mode. Finally, an optimization was carried out regarding the driving motor control strategy and the motor structure, along with the control measure to reduce the variation of the electric voltage and current.
2016-04-05
Technical Paper
2016-01-1149
Hanqi Yue, Xintian Lu, Xuesong Li, Bingzhao Gao, Hong Chen
A novel torque-coupling architecture for hybrid electric vehicles is proposed to exploit energy-reduction potential. One engine and two motors serve as the power sources. The torque-coupling device is based on automated manual transmission (AMT), which is highly efficient and provides six gears for the engine and three gears for each motor to enable the engine and the motors to work at high-efficiency levels in most cases. A smooth shifting process without torque hole is also attained through a deliberately designed control scheme for the power sources and the sliding sleeves. The proposed power-shift AMT (P-AMT) has no wet clutch and hydraulic torque converter. Thus, it has a higher efficiency than AT and CVT. The P-AMT also has no dry clutch, so friction loss can be avoided as well. In this paper, working mode and gear shifting process of P-AMT are described in detail. The performance of P-AMT is evaluated through simulations by commercial software AMESim.
2016-04-05
Technical Paper
2016-01-1385
Rongchao Jiang, Dengfeng Wang
Vehicle ride comfort, handling, road friendliness and roll stabilities are the main performances for heavy vehicles, which are strongly affected by suspension system. Although a relatively soft suspension is considered beneficial for both vehicle ride and road-friendliness, it tends to deteriorate vehicle handling quality and roll stability. As a consequence, the suspension designs and tuning aiming at improving different vehicle performance measures have been receiving increasing attention. Therefore, this study presents a hybrid optimization approach of TOPSIS-based Taguchi method and entropy measurement for the determination of the optimal suspension parameters to achieve an enhanced compromise among ride comfort, road friendliness and handling stabilities. In this paper, the full multi-body dynamic vehicle model of a self-dumping truck is developed using software ADAMS/Car and the vehicle model is then validated through ride comfort road tests.
2016-04-05
Technical Paper
2016-01-0440
Li Jie, Wang Wenzhu, Gao Xiong, Zhang Zhenwei
The heavy truck often moves in a poor, long-distance and high-speed freight state environment, so drivers are easy to fatigue and goods are easily damaged. At the same time, compared to the passenger car, the ride comfort of heavy trucks has a lot of room for improvement. Therefore, the research on the ride comfort of heavy trucks becomes crucial.Based the elastic theory of Euler-Bernoulli beam with both free ends, a 6 DOF half rigid-elastic vibration model of the vertical dynamic response is developed, which is more suitable to the actual movement of heavy trucks. The DOFs include: vertical displacements of the body and each of two axles; the pitch displacement of the body; the first and second order bending displacements of the body. The root mean square values of body acceleration, dynamic deflections and relative dynamic loads act as evaluation index.
2016-04-05
Technical Paper
2016-01-0153
Qingkun Jiang, Weiwen Deng, Bing Zhu
This paper studies intelligent vehicle threat assessment aimed to improve trajectory planning for intelligent vehicles based on the random tree (RRT) approach, which has been widely adopted in the prior art for complex and dynamic traffic environment. The proposed RRT approach integrates the threat assessment in the trajectory planning and proves to be more efficient and effective compared to the hierarchical framework. The contribution of this paper is on the threat assessment that takes into account not only obstacle avoidance but also stability. The simulation is conducted and the results show that the proposed method works as expected and is valid and effective.
2015-09-27
Technical Paper
2015-01-2708
Yi Yang, Liang Chu, Liang Yao, Chong Guo
Abstract During the vehicle braking, the Regenerative braking system (RBS) transforms the kinetic energy into electric power, storing it in the power sources. To secure the baking process, it is required to use hydraulic braking pressure to coordinately compensate the regenerative braking pressure. The traditional hydraulic pressure control algorithm which is used in regenerative braking system coordinated control has obvious laddering effect in braking. Unit control cycle pressure deviations seriously affect the comfort and the braking feeling on the vehicle.
2015-06-15
Journal Article
2015-01-2260
Tianze Shi, Shuming Chen, Dengfeng Wang
Abstract Artificial intelligence systems are highly accepted as a technology to offer an alternative way to tackle complex and non-linear problems. They can learn from data, and they are able to handle noisy and incomplete data. Once trained, they can perform prediction and generalization at high speed. The aim of the present study is to propose a novel approach utilizing the adaptive neuro-fuzzy inference system (ANFIS) and the fuzzy clustering method for automotive ride performance estimation. This study investigated the relationship between the automotive ride performance and relative parameters including speed, spring stiffness, damper coefficients, ratios of sprung and unsprung mass. A Takagi-Sugeno fuzzy inference system associated with artificial neuro network was employed. The C-mean fuzzy clustering method was used for grouping the data and identifying membership functions.
2015-04-14
Technical Paper
2015-01-0615
Li Jie, Wang Wenzhu, Gao Xiong
Abstract In order to study the influence of body flexibility on the truck ride comfort, a 4 DOF half vibration model of truck based on the motion synthesis between rigid body and body flexibility is established using elastic beam theory of equal section with both free ends. At the same time, a corresponding 2 DOF rigid vibration model is also built. The frequency response functions of system and response variables of two models are derived based on front wheel. The power spectral densities and the root mean square values of body acceleration, dynamic deflections and relative dynamic loads are obtained. By comparing the simulation results of rigid-elastic model and rigid model, it shows that body flexibility has a great impact on truck ride comfort and it cannot be ignored.
2015-04-14
Technical Paper
2015-01-0635
Changxin Wang, Wenku Shi, Zhijun Guo, Meilan Liu
Abstract For the roll vibration problem of a Truck, a 4-DOF roll vibration model of its front suspension system was built. According to dynamics theory, the complex modal vibration modes of the model were all obtained. At the same time, the frequency response functions of frame roll angle acceleration, the relative dynamic load of wheel and the suspension dynamic deflection were respectively presented. Then their characteristics were respectively researched. In the process of characteristic analysis, a new system parameter was proposed, which is the space ratio of the space between suspensions of left and right sides and the wheel track of the front axle (space ratio in short). At last, the influence of system parameters on the vibration transmission property was also reserached, which included the natural frequency of the frame, the damping ratio, the stiffness ratio, the mass ratio, the rotational inertia ratio and the space ratio.
2015-04-14
Technical Paper
2015-01-1108
Hongqing Chu, Yong Chen, Lishu Guo, Bingzhao Gao, Hong Chen
Abstract In order to improve the drivability and reduce the clutch friction loss, low-cost slope sensor is used in hill-start control of AMT vehicles. After the power spectrum analysis of the original signal and the design of the digital filter, the angle of the slope is obtained with short enough delay and small enough noise. By using this slope angle information, slope resistance force can be calculated online so that the vehicle can be prevented from sliding backward and optimal launch control can be realized. The digital filter of slope angle signal and the optimal controller of dry clutch engagement are embedded in the TCU (Transmission Control Unit) of a micro-car Geely Panda. Real-vehicle experiments are carried out with optimal clutch controller, which shows that the hill-start with low-cost slope sensor and optimal clutch controller can provide successful vehicle launch with little driveline shock.
2015-04-14
Technical Paper
2015-01-1216
Dafeng Song, Chang Zhang, Nannan Yang, Mingli Shang, Yujun Peng
Abstract Hybrid Electric Vehicles with a power split system provide a variety of possibilities to promote the fuel economy of vehicles and better adapt to various driving conditions. In this paper, a new power split system of a hybrid electric bus which consists of double planetary gear sets and a clutch is introduced. The system is able to decouple both the torque and speed of the engine from the road load, which makes it possible for the engine to operate on its optimal operation line (OOL). Considering the features of the system configuration and bus driving cycle, the driving mode of the bus is divided into Electric Vehicle (EV) mode, Electric Variable Transmission (EVT) mode and Parallel mode. By controlling the engagement of the clutch at high vehicle speed (after the mechanical point), the system operates in the parallel mode rather than EVT mode.
2015-04-14
Technical Paper
2015-01-1348
Rongchao Jiang, Dengfeng Wang
Abstract A detailed multi-body dynamic model of a passenger car was modeled using ADAMS/Car and then checked by the ride comfort and handling stability test results in this paper. The performance criterion for ride comfort evaluation was defined as the overall weighted acceleration root mean square (RMS) value of car body floor, while the roll angle and lateral acceleration of car body were considered as evaluation indicators for handling stability performance. Simultaneously, spring stiffness and shock absorber damping coefficients of the front and rear suspensions were taken as the design variables (also called factors), which were considered at three levels. On this basis, a L9 orthogonal array was employed to perform the ride and handling simulations.
2015-04-14
Technical Paper
2015-01-0472
Rongchao Jiang, Dengfeng Wang
Abstract In this study, with the aim of reducing fuel consumption and improving power performance, the optimization for the driveline parameters of a self-dumping truck was performed by using a vehicle performance simulation model. The accuracy of this model was checked by the power performance and fuel economy tests. Then the transmission ratios and final drive ratio were taken as design variables. Meanwhile, the power performance of the self-dumping truck was evaluated through standing start acceleration time from 0 to 70km/h, maximum speed and maximum gradeability, while the combined fuel consumption of C-WTVC drive cycle was taken as an evaluation index of fuel economy. The multi-objective optimization for the power performance and fuel economy was then performed based on particle swarm optimization algorithm, and the Pareto optimal set was obtained. Furthermore, the entropy method was proposed to determine the weight of fuel consumption and acceleration time.
2015-04-14
Journal Article
2015-01-0501
Dengfeng Wang, Rongchao Jiang
Abstract In this paper, the performance simulation model of a domestic self-dumping truck was established using AVL-Cruise software. Then its accuracy was checked by the power performance and fuel economy tests which were conducted on the proving ground. The power performance of the self-dumping truck was evaluated through standing start acceleration time from 0 to 70km/h, overtaking acceleration time from 60 to 70km/h, maximum speed and maximum gradeability, while the composite fuel consumption per hundred kilometers was taken as an evaluation index of fuel economy. A L9 orthogonal array was applied to investigate the effect of three matching factors including engine, transmission and final drive, which were considered at three levels, on the power performance and fuel economy of the self-dumping truck. Furthermore, the grey relational grade was proposed to assess the multiple performance responses according to the grey relational analysis.
2015-04-14
Journal Article
2015-01-0547
Dengfeng Wang, Rongchao Jiang
Abstract In this paper, the dynamic stress of the front subframe of a passenger car was obtained using modal stress recovery method to estimate the fatigue life. A finite element model of the subframe was created and its accuracy was checked by modal test in a free hanging state. Furthermore, the whole vehicle rigid-flexible coupling model of the passenger car was built up while taking into account the flexibility of the subframe. Meanwhile, the road test data was used to verify the validity of the dynamic model. On this basis, the modal displacement time histories of the subframe were calculated by a dynamic simulation on virtual proving ground consisting of Belgian blocks, cobblestone road and washboard road. By combining the modal displacement time histories with modal stress tensors getting from normal mode analysis, the dynamic stress time histories of the subframe were obtained through modal stress recovery method.
2015-03-10
Technical Paper
2015-01-0016
Changxin Wang, Wenku Shi, Zan Li, Fuxiang Guo
Abstract This paper presents the study of chassis tuning of a commercial vehicle, which has a rear suspension with dual stage leaf spring assembly and a front suspension with double wishbone torsion bar. To balance the handling and ride performance of the vehicle, it is necessary to tune the key suspension parameters of the chassis including the dual stage stiffness of the leaf spring, the contact load of the leaf spring, the torsional rigidity of the torsion bar, the force curve of the front and rear dampers etc. The chassis tuning process of a physical commercial vehicle was first put forward. In the proposed flowchart, the kinematics and statics of front & rear suspensions were checked at the beginning of the tuning. Then the tire mechanical characteristics were tested by using a plate-type tire tester and the inertial parameters of the vehicle were indirectly measured. The K&C characteristics of front and rear suspensions were also tested and compared with the benchmark vehicle's.
2015-03-10
Technical Paper
2015-01-0026
Wenku Shi, Changxin Wang, Zan Li
Abstract In order to improve the handling and stability of a light bus at high speed, a virtual model was established in Adams-Car and its anti-roll bar and bushing parameters were virtually optimized. The tyre mechanical characteristics were firstly tested by using a plate-type tyre tester and the Magic Formula parameters of the tyre were obtained. Then the virtual bus model's handling performance were studied by the simulation of central steering test and steady static circular test. An optimal matching method was put forward. By using genetic algorithm to conduct optimization, the optimised parameters were obtained. After that the anti-roll bar and bushing samples were respectively manufactured. At last, the comparative trials were performed in an automotive proving ground, and the subjective evaluation of the light bus's handling and stability was taken by three specialized assessors.
2015-03-10
Technical Paper
2015-01-0042
Changxin Wang, Wenku Shi, Yiming Wang, Teng Shi
Abstract This paper presented one calculation method of the contact load, which is the load acted on the spring at the moment when the second-level stiffness of the spring just begins to work. In the proposed method, the contact load calculation mainly based on the dynamic load of the unsprung mass and the road grades and the commonly driving speed were also considered. A semiempirical formula of the contact load was put forward. Then the contact load of the commercial bus's rear suspension was respectively calculated by using the proposed formula and traditional methods(geometric mean method and average load method) to compare each other and to verify the new method. Later, the spring samples were respectively manufactured based on the calculation results. At last, the validation tests were respectively performed in an automotive proving ground.
2014-09-30
Technical Paper
2014-01-2291
Dong Zhang, Changfu Zong, Guoying Chen, Pan Song, Zexing Zhang
Abstract A full drive-by-wire electric vehicle, named Urban Future Electric Vehicle (UFEV) is developed, where the four wheels' traction and braking torques, four wheels' steering angles, and four active suspensions (in the future) are controlled independently. It is an ideal platform to realize the optimal vehicle dynamics, the marginal-stability and the energy-efficient control, it is also a platform for studying the advanced chassis control methods and their applications. A centralized control system of hierarchical structure for UFEV is proposed, which consist of Sensor Layer, Identification and Estimation Layer, Objective Control Layer, Forces and Motion Distribution Layer, Executive Layer. In the Identification and Estimation Layer, identification model is established by utilizing neural network algorithms to identify the driver characteristics. Vehicle state estimation and road identification of UFEV based on EKF and Fuzzy Logic Control methods is also conducted in this layer.
2014-09-30
Technical Paper
2014-01-2285
Dong Zhang, Changfu Zong, Ying Wan, Hongyu Zheng, Wei-qiang Zhao
Abstract Electronic braking system (EBS) of commercial vehicle is developed based on Anti-lock Braking System (ABS), for the purpose of enhancing the braking performance. Based on the previous study, this paper aims at the development and research on the control strategy of advanced electronic braking system for commercial vehicle, which mainly includes braking force distribution and multiple targets control strategy. In the study of braking force distribution control strategy, the mass of vehicle and the axle loads will be calculated dynamically and the braking force of each wheel will be distributed regarding to the axle loads. The braking intention recognition takes the brake pad wear into account when braking uncritically, so it can detect a difference in the pads between the front and the rear axles. The brake assist strategy supports the driver during emergency braking and the braking distance is shortened by the reduction of the braking system response time.
2014-09-30
Technical Paper
2014-01-2286
Ying Wan, Dong Zhang, Zhao Weiqiang, Changfu Zong, Jongchol Han
Pneumatic Electric Braking System (EBS) is getting widely spread for commercial vehicles. Pneumatic EBS improves the problem of slow response of traditional pneumatic braking system by implementing brake-by-wire. However, the time-delay response and hysteresis of some electro-pneumatic components and some other issues decrease the response and control accuracy of the pneumatic EBS.
2014-04-01
Technical Paper
2014-01-1452
Han Wu, Ming Huo, Nan Zhou, Karthik Nithyanandan, Chia-Fon Lee, Chunhua Zhang, Jiang Lin
Abstract Acetone-Butanol-Ethanol (ABE), an intermediate product in the ABE fermentation process for producing bio-butanol, is considered a promising alternative fuel because it not only preserves the advantages of oxygenated fuel which typically emit less pollutants compared to conventional diesel, but also lowers the cost of fuel recovery for each individual component during the fermentation. With the development of advanced ABE fermentation technology, the volumetric percentage of acetone, butanol and ethanol in the bio-solvents can be precisely controlled. In this respect, it is desirable to estimate the performance of different ABE blends to determine the best blend and optimize the production process accordingly. ABE fuels with different component ratio, (A: B: E: 6:3:1; 3:6:1; 0:10:0, vol. %), were blended with diesel and tested in a constant volume chamber.
2014-04-01
Technical Paper
2014-01-0865
Yuhang Chen, Yunfeng Ji, Konghui Guo
Abstract In this paper, a sliding mode observer for estimating vehicle slip angle and tire forces is developed. Firstly, the sliding mode observer design approach is presented. A system damping is included in the sliding mode observer to speed the observer convergence and to decrease the observer chattering. Secondly, the sliding mode observer for vehicle states is developed based on a 7 DOF embedded vehicle model with a nonlinear tire model ‘UniTire’. In addition, since the tire lateral stiffness is sensitive to the vertical load, the load transfers are considered in the embedded model with a set of algebraic equations. Finally, a simulation evaluation of the proposed sliding mode observer is conducted on a validated 14 DOF vehicle model. The simulation results show the model outputs closely match the estimations by the proposed sliding mode observer.
2014-04-01
Technical Paper
2014-01-0929
Changxin Wang, Wenku Shi, Qinghua Zu
Abstract Aiming at the difficulty of sovling the stiffness calculation of taper-leaf spring with variable stiffness, a combined method was proposed, which combine superposition method and finite difference method. Then the calculation results of different differential segments were compared with experimental results. The compared results show that the proposed method is effective and simple. So it has some practical significance in designing the taper-leaf spring. In addition, based on the stiffness test of the taper-leaf spring, the proper adjustments to the correction factor of the single parabolic leaf spring stiffness formula was recommended(ξ =0.92-0.96).
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