A tunable fuzzy logic controller for the vehicle semi-active suspension system

On the basis of analyzing the system constitution of vehicle semi-active suspension, a 4-DOF (degree of freedom) dynamic model is established. A tunable fuzzy logic controller is designed by using without quantification method and taking into account the uncertainty, nonlinearity and complexity of parameters for a vehicle suspension system. Simulation to test the performance of this controller is performed under random excitations and definite disturbances of a C grade road, and the effects of time delay and changes of system parameters on the vehicle suspension system are researched. The numerical simulation shows that the performance of the designed tunable fuzzy logic controller is effective, stable and reliable.

Analyses and Simulation of Fuzzy Logic Control for Suspension System of a Track Vehicle

The vibration caused by terrible road excitation affects the ride quality and safety of track vehicles. The vibration control of suspension systems is a very important factor for modern track vehicles. A fuzzy logic control for suspension system of a track vehicle is presented. A mechanical model and a system of difft, rential equations of motion taking account of the mass of loading wheel are established. Then the fuzzy logic control is applied to control the vibration of suspension system of track vehicles for sine signal and random road surfaces. Numerical simulation shows that the maximum acceleration of suspension system can be reduced to 44 % of the original value for sine signal road surface, and the mean square root of acceleration of suspension system can be reduced to 21% for random road surface. Therefore, the proposed fuzzy logic control is an efficient method for the suspension systems of track vehicles.

Fuzzy Logic Control for Suspension Systems of Tracked Vehicles

A scheme of fuzzy logic control for the suspension system of a tracked vehicle is presented. A mechanical model for the whole body of a tracked vehicle, which is totally a fifteen-degree-of-freedom system, is established. The model includes the vertical motion, the pitch motion as well as the roll motion of the tracked vehicle. In contrast to most previous studies, the coupling effect among the vertical, the pitch and the roll motions of the suspension system of a tracked vehicle is considered simultaneously. The simulation of fuzzy logic control under road surface with random excitation shows that the acceleration, pitch angle and roll angle of suspension system can be efficiently controlled.

Test and numerical investigations on static and dynamic characteristics of extra-wide concrete self-anchored suspension bridge under vehicle loads

The present work is aimed at studying the mechanic properties of the extra-wide concrete self-anchored suspension bridge under static and dynamic vehicle loads. Based on the field test using 12 heavy trucks and finite element simulations, the static deformations of different components, stress increments and distributions of the girder, as well as the vibration characteristics and damping ratio of the Hunan Road Bridge were analyzed, which is the widest self-anchored suspension bridge in China at present. The dynamic responses were calculated using the Newmark-β integration method assisted by the simulation models of bridge and vehicles, the influences on the dynamic impact coefficient(DIC) brought by the vehicle parameters, girder width, eccentricity travel and deck flatness were also researched. The spatial effect of the girder is obvious due to the extra width, which performs as the stress increments distribute unevenly along the transverse direction, and the girder deflections and stress increments of the upper plate change as a "V" and "M" shape respectively under the symmetrical vehicle loads affected by the shear lag effect, cross slope and local effect of the wheels, the maximum of stress increments are located in the junctions with the inner webs. The obvious girder torsional deformation and the apparent unevenness of the hanger forces between the two cable planes under the eccentric vehicle loads, together with the mode shapes such as the girder transverse bending and torsion which appear relatively earlier, all reflect the weakened torsional rigidity of the extra-wide girder. The transverse displacements of towers are more obvious than the longitudinal ones. As for the influences on the DIC, the static effect of the heavier vehicles plays a major role when pass through with a higher speed and the changes of vehicle suspension stiffness generate greater impacts than the suspension damp. The values of DIC in the vehicle-running side during the eccentric travel, affected by the restricts from the static effects of the eccentric moving trucks, are significantly smaller than the vehicle-free side, the increase in the road roughness is the most sensitive one among the above influential factors. The results could provide references for the design, static and dynamic response analysis of the similar extra-wide suspension bridges.

SEMI-ACTIVE CONTROL OF VEHICLE SUSPENSION WITH MAGNETO-RHEOLOGICAL DAMPERS:PART III—EXPERIMENTAL VALIDATION

A hardware-in-the-loop （HIL） test and simulation platform is developed in the laboratory, so as to validate the performance characteristics of the proposed skyhook-based asymmetric semi-active controller in Part I, and examine the validity of the proposed MR-damper model in a system surrounding. A real-time monitor is designed to assess and monitor the responses of the quarter-vehicle model in the HIL platform, and to select the excitation, controller synthesis, and the output displays. A drive current circuit hardware employing PID feedback technique is developed to compensate for the time delays from the servo-controller and drive current circuit, in which a small resistance is integrated in the current amplifier circuit to provide the feedback signal. The experiments were performed to measure the responses of the quarter-vehicle MR-suspension models with fixed current and the proposed semi-active MR-damping variations, under harmonic, rounded pulse and random road excitations. The measured data were compared with the corresponding model results to examine the model and controller validity, and revealed generally good agreements in the model and tested results and very little sensitivity of the tested responses to variations in the sprung mass. The HIL test results validate the effectiveness of the proposed skyhook-based semi-active asymmetric controller and its high robustness against the vehicle load variations in view of the intelligent vehicle suspension design.

A Study of IVECO Automobile Suspension System by Simulation

For analyzing the ride comfort performance, a dynamical model of an IVECO vehicle was built in this paper. The simulation study of the IVECO vehicle suspension performance on random uneven road is carried out by means of the dynamical model. The effects of suspension system parameters on the vehicle ride comfort parameter, i. e. , the root mean square （ RMS） of the vibrating acceleration of the vehicle body, are analyzed. The optimal parameters and initial value of the suspension system can be determined by the model and the method of this paper.

Aerodynamic drag analysis of double-deck container vehicles with different structures

To study the aerodynamic performance of a new six-axis X2K double-deck container vehicle, numerical simulation was done based on three-dimensional, steady Navier-Stokes equations and k-e turbulence model. The results show that the pressure on the front surface of vehicle is positive, and others are negative. The maximum negative one appears as a ＂gate＂ shape on front surfaces. The pressure on vehicle increases with train speed, and pressure on vehicles with cross-loaded structure is smaller than that without it. The airflow around vehicles is symmetrical about train vertical axis, and the flow velocity decreases gradually along the axis to ground. Airflow around vehicles with cross-loaded structure is weaker than that without the structure. The aerodynamic drag increases linearly with the train speed, and it is minimum for the mid-vehicle. The linear coefficient for mid-vehicle without cross-loaded structure is 29.75, nearly one time larger than that with the structure valued as 15.425. So, from the view-point of aerodynamic drag, the cross-loaded structure is more reasonable for the six-axis X2K double-deck container vehicle.

Evaluation of High-Speed Track Quality Using Dynamic Simulation of Vehicle-Track Interaction

Track quality is a determinant factor for evaluating the overall performance of vehicle track interaction with respect to safety, ride quality and maintenance. Important parameters specifying the general quality of the track include track geometry (undamped) and track stiffness (damped), which can be evaluated by measurements taken along with track sections. A new co-simulation model based on Finite Element Method (FEM) and Multi Body Simulation (MBS) is built for the detailed description of track quality and its contribution to vehicle track interaction without simplifying the track structure as interconnected single elements. The simulation models and tools have been validated with the help of measured track geometry, track stiffness and dynamic wheel rail forces along the track sections of high speed lines. A comparative study between high speed lines using conventional ballasted track and ballastless track showed a significantly better quality in ballastless track sections. The dynamic forces which were determined by simulations and verified by measurements along the ballastless track section were comparatively less than the specified limits by German regulations for ballastless track design. Lower levels of dynamic forces can be utilized for optimization of track design and installation procedures with respect to lower initial costs.

Reduction of global effects on vehicles after IED detonations

Global effects caused by the detonation of an IED near a military vehicle induce subsequent severe acceleration effects on the vehicle occupants.Two concepts to minimize these global effects were developed,with the help of a combined method based on a scaled experimental technology and numerical simulations.The first concept consists in the optimization of the vehicle shape to reduce the momentum transfer and thus the occupant loading.Three scaled V-shaped vehicles with different ground clearances were built and compared to a reference vehicle equipped with a flat floor.The second concept,called dynamic impulse compensation(DIC),is based on a momentum compensation technique.The principal possibility of this concept was demonstrated on a scaled vehicle.In addition,the numerical simulations have been performed with generic full size vehicles including dummy models,proving the capability of the DIC technology to reduce the occupant loading.

Procedural simulation method for aggregating charging load model of private electric vehicle cluster

The usage of each private electric vehicle(PrEV)is a repeating behavior process composed by driving,parking,discharging and charging,in which PrEV shows obvious procedural characteristics.To analyze the procedural characteristics,this paper proposes a procedural simulation method.The method aggregates the behavior process regularity of the PrEV cluster to model the cluster’s charging load.Firstly,the basic behavior process of each PrEV is constructed by referring the statistical datasets of the traditional private non-electric vehicles.Secondly,all the basic processes are set as a simulation starting point,and they are dynamically reconstructed by several constraints.The simulation continues until the steady state of charge(SOC)distribution and behavior regularity of the PrEV cluster are obtained.Lastly,based on the obtained SOC and behavior regularity information,the PrEV cluster’s behavior processes are simulated again to make the aggregating charging load model available.Examples for several scenarios show that the proposed method can improve the reliability of modeling by grasping the PrEV cluster’s procedural characteristics.

电动汽车驱动电机与负载模拟系统建模及电弧故障仿真研究

电弧故障是引发电动汽车电气火灾的重要原因之一。电动汽车行驶工况复杂,电机及其驱动系统电压高、电流大,且其电弧故障随机性强、隐蔽性高导致真车故障实验难以开展,因此提出一种借助小功率电机与负载系统模拟故障的方法,以便快速开展大量实验,研究电弧故障特性。首先,在电动汽车负载转矩计算和等效缩放的基础上搭建了模拟实验平台,采集三相永磁同步电机线路串联电弧故障电流。其次,运用MATLAB软件构建空间矢量脉宽调制控制的电动汽车驱动电机与负载模拟系统,引入Cassie电弧故障模型并进行改进,对电动汽车三相永磁同步电机线路串联电弧故障展开仿真分析。最后,采用基于平肩宽度占比和小波包分解能量占比的特征提取方法,将仿真数据与实测数据进行比较并定量评价。结果表明,所提出的高斯电弧故障复合模型的相对平均误差最小,仅为7.6%。所构建的仿真系统可有效模拟实际线路的电弧故障,对电动汽车电气火灾的防控具有重要意义。

履带车辆主动悬挂多点布置优化

为实现履带车辆主动悬挂减振性能和能耗达到综合最优,基于正交试验方法开展履带车辆主动悬挂多点布置优化设计。首先,建立了履带车辆悬挂系统动力学模型,并通过道路模拟试验验证了该模型的合理性;其次,开展了履带车辆悬挂系统正交试验,分析了4种典型路面下各子悬挂对悬挂系统减振性能影响的敏感性;最后,设计了主动悬挂作动器的6个布置方案,通过建立基于线性二次最优(linear quadratic regulator,简称LQR)控制的履带车辆主动悬挂动力学模型,分析了典型路面下各布置方案对悬挂系统减振性能的影响规律及能耗变化规律。结果表明,通过对履带车辆主动悬挂作动器的布置优化,可以实现悬挂减振性能和能耗之间的平衡。

大跨度钢-混结合梁悬索桥涡激振动控制指标体系研究

为保证已建桥梁发生涡激振动后桥梁结构的安全以及桥上行车和行人安全,提出综合考虑人员舒适性、结构受力和停车线形三方面的大跨度钢-混结合梁悬索桥涡激振动控制指标体系。该体系包含9项指标,分别为驾乘人员舒适度、驾乘人员晕动症、行人舒适度(狄克曼指标)、加劲梁强度、加劲梁应力、加劲梁挠度、桥面纵坡、竖曲线半径和停车视距。以武汉鹦鹉洲长江大桥为背景,分别计算了“限速”和“封桥”2个交通管制措施下9项指标对应的涡激振动振幅限值。在此基础上,将9项指标对应的涡激振动振幅限值的最小值作为涡激振动限值建议取值。结果表明:当该桥发生低阶竖弯涡激振动(VS1、VAS1)时,涡激振动的控制因素为加劲梁挠度指标;当大桥发生VAS2模态的竖弯涡激振动时,涡激振动由驾乘人员晕动症指标和行人舒适度指标共同控制;当大桥发生高阶竖弯涡激振动(VAS3、VAS4)时,涡激振动由行人舒适度指标控制。涡激振动控制指标体系及限值标准的计算框架可适用于不同桥型涡激振动限值的计算。

爆炸作用下超宽自锚式悬索桥动力响应研究

为研究超宽混凝土自锚式悬索桥在爆炸荷载作用下动力响应和毁伤特征,以某超宽混凝土自锚式悬索桥为工程背景,采用数值模拟文法,分析桥面近距爆炸作用下超宽箱梁顶面破口形态、底板竖向位移等动力响应。首先,利用Solidworks软件和Hypermesh软件建立整体桥梁的精细化有限元模型;其次,采用Ansys/LS-DYNA软件和*LOAD_BLAST_ENHANCED(LBE)方法施加爆炸荷载,并结合文献中混凝土构件爆炸试验结果验证计算方法的可靠性;最后,参数化分析不同炸药当量和沿横纵桥向不同爆炸位置工况下桥梁的动力响应。结果表明:当TNT当量为300 kg时,爆心正下方混凝土单元应力达极限值发生失效,形成椭圆形贯穿破口。随着TNT药量的增大,爆心正下方底板中心处的竖向位移峰值不断增大,1 000 kg药量工况下爆炸50 ms后竖向位移达135.9 mm。随着至爆心的距离增大,底板竖向位移减小,且竖向位移的增大速度减缓。吊杆内力变化与相连的箱梁底板竖向位移具有相关性,箱梁底板竖向位移越大,吊杆内力变化达到第一峰的峰值越高。相同爆炸当量工况下,爆心处于横、纵桥向不同位置时,超宽箱梁动力响应和破口形态的区别主要由横隔梁、腹板的支撑和约束作用不同引起。研究结果可为混凝土自锚式悬索桥的抗爆防护与加固提供重要依据。

基于ADAMS/CAR的某SUV汽车操纵稳定性仿真实验分析及优化

操纵稳定性是车辆正常行驶时受到外界扰动后保持稳定运行或迅速恢复稳定的一种能力,对车辆安全平稳运行至关重要。为优化车辆的操纵稳定性,对某SUV汽车进行动力性分析,建立物理模型和数学模型,阐述悬架对汽车操纵稳定性的影响。采用ADAMS/CAR进行整车建模,运用MATLAB软件对操纵稳定性评价指标进行评分。选取悬架的力学特性参数作为优化变量,以操纵稳定性评价指标的评分作为优化目标,通过对比选取最优方案。研究结果表明:NGSA-II算法对道路实验评价指标的优化效果较好,能够显著提升整车的操纵稳定性。

Global modeling and simulation of vehicle to analyze the inertial parameters effects

This paper mainly studies the comparison of the global vehicle models and the effects of the inertial parameters due to the center of gravity(CG)positions when we consider that the vehicle has only one CG.This paper proposes a new nonlinear model vehicle model which considers both unsprung mass and sprung mass CG.The CG positions and inertial parameters effects are analyzed in terms of the published vehicle dynamics models.To this end,two 14 degree-of-freedom(DOF)vehicle models are developed and compared to investigate the vehicle dynamics responses due to the different CG height and inertial parameters concepts.The proposed models describe simultaneously the vehicle motion in longitudinal,lateral and vertical directions as well as roll,pitch and yaw of the vehicle about corresponding axis.The passive and active moments and the forces acting on the vehicle are also described and they are considered as a direct consequence of acceleration,braking and steering maneuvers.The proposed model M1 takes both the CG of sprung mass,unsprung mass and total vehicle mass into account.The second model M2 assumes that the vehicle is one solid body which has a single CG as reported in majority of literature.The two vehicle models are compared and analyzed to evaluate vehicle ride and handling dynamic responses under braking/acceleration and cornering maneuvers.Simulation results show that the proposed model M1 could offer analytically some abilities and driving performances,as well as improved roll and pitch in a very flexible manner compared to the second model M2.

考虑电池老化的电动汽车中长期充电负荷预测方法

随着电动汽车市场份额逐年上升,受限于区域内动力电池容量大小的电动汽车充电负荷占总用电负荷的比例不断提高。为此,提出一种考虑电池老化的电动汽车中长期充电负荷预测方法。首先,构建考虑电池老化的区域电动汽车电池总容量预测模型,预测电池老化带来的总容量衰减以及更换新电池和车辆数目增长带来的总容量上升。其次,构建考虑温度变化的动力电池老化特性估计模型,预估每次充电后电池最大容量、可充电量和续航电量,当电池最大容量不足以保证车辆安全运行时,对车辆更换新电池。最后,构建考虑充电成本的车辆行为仿真模型,模拟车辆出行和充电过程;借助模糊C均值法对不同种类电动汽车充电负荷进行划分,通过蒙特卡洛模拟与线性加权确定区域内电动汽车中长期负荷。仿真结果表明,随着车辆使用时间的增加,年负荷曲线波动程度不断变大;相较于新车,电池老化后单位车辆周均用电负荷峰值出现的时间会提前,且负荷峰谷差也会增大。

基于多智体的自动驾驶汽车停车空载收费策略

为了制订自动驾驶车辆(AV)停车需求管理方案,搭建多智能体停车模拟框架,提出2种空载行驶收费策略:基于行驶距离的静态收费和基于道路拥堵水平的动态收费,研究费率计算方法.建立空载行驶收费策略下停车场停车、居住地停车及持续空载巡航3种停车模式的成本函数,使用logit模型描述不同停车模式下的选择行为.利用Simulation of urban mobility(SUMO),以南宁市主城区为例开展大规模路网下的仿真实验,研究2种策略下的AV停车行为及路网运行状态变化.仿真结果表明,静态收费策略和动态收费策略下的AV空载行驶里程分别减少了20.16%和10.85%,车辆总延误分别降低了39.80%和43.52%;动态收费策略能够灵活地根据路况变化进行实时调整,路网运行效率提升更显著.

基于虚拟样机的某多轴车辆制动轴荷特性分析

文中对某多轴单纵臂车辆的行动部分进行了虚拟样机建模,依据总体任务指标及相关法规对其进行了不同制动强度工况下的制动过程仿真.通过对仿真结果的综合比较,分析得到了各轴在不同制动强度下轴荷动态分布特性,为车辆行动部件及车体的结构强度校核设计,以及各轴制动力的匹配优化设计提供了参考依据.