Influence of Tire Dynamics on Slip Ratio Estimation of Independent Driving Wheel System

The independent driving wheel system, which is composed of in-wheel permanent magnet synchronous motor（I-PMSM） and tire, is more convenient to estimate the slip ratio because the rotary speed of the rotor can be accurately measured. However, the ring speed of the tire ring doesn’t equal to the rotor speed considering the tire deformation. For this reason, a deformable tire and a detailed I-PMSM are modeled by using Matlab/Simulink. Moreover, the tire/road contact interface（a slippery road） is accurately described by the non-linear relaxation length-based model and the Magic Formula pragmatic model. Based on the relatively accurate model, the error of slip ratio estimated by the rotor rotary speed is analyzed in both time and frequency domains when a quarter car is started by the I-PMSM with a definite target torque input curve. In addition, the natural frequencies（NFs） of the driving wheel system with variable parameters are illustrated to present the relationship between the slip ratio estimation error and the NF. According to this relationship, a low-pass filter, whose cut-off frequency corresponds to the NF, is proposed to eliminate the error in the estimated slip ratio. The analysis, concerning the effect of the driving wheel parameters and road conditions on slip ratio estimation, shows that the peak estimation error can be reduced up to 75% when the LPF is adopted. The robustness and effectiveness of the LPF are therefore validated. This paper builds up the deformable tire model and the detailed I-PMSM models, and analyzes the effect of the driving wheel parameters and road conditions on slip ratio estimation.

OPTIMAL TORQUE CONTROL STRATEGY FOR PARALLEL HYBRID ELECTRIC VEHICLE WITH AUTOMATIC MECHANICAL TRANSMISSION

In parallel hybrid electrical vehicle （PHEV） equipped with automatic mechanical transmission （AMT）, the driving smoothness and the clutch abrasion are the primary considerations for powertrain control during gearshift and clutch operation. To improve these performance indexes of PHEV, a coordinated control system is proposed through the analyzing of HEV powertrain dynamic characteristics. Using the method of minimum principle, the input torque of transmission is optimized to improve the driving smoothness of vehicle. Using the methods of fuzzy logic and fuzzy-PID, the engaging speed of clutch and the throttle opening of engine are manipulated to ensure the smoothness of clutch engagement and reduce the abrasion of clutch friction plates. The motor provides the difference between the required input torque of transmission and the torque transmitted through clutch plates. Results of simulation and experiments show that the proposed control strategy performs better than the contrastive control system, the smoothness of driving and the abrasion of clutch can be improved simultaneously.

Modeling and Control of Parallel Hybrid Electric Vehicle Using Sea-Lion Optimization

This paper develops a parallel hybrid electric vehicle(PHEV)propor-tional integral controller with driving cycle.To improve fuel efficiency and reduce hazardous emissions in hybrid electric vehicles(HEVs)combine an electric motor(EM),a battery and an internal combustion engine(ICE).The electric motor assists the engine when accelerating,driving longer highways or climbing hills.This enables the use of a smaller,more efficient engine.It also makes use of the concept of regenerative braking to maximize energy efficiency.In a Hybrid Electric Vehicle(HEV),energy dissipated while braking is utilized to charge the battery.The proportional integral controller was used in this paper to analyze engine,motor performance and the New European Driving Cycle(NEDC)was used in the vehicle driving test using Matlab/Simulink.The proportional integral controllers were designed to track the desired vehicle speed and manage the vehi-cle’s energyflow.The Sea Lion Optimization(SLnO)methods were created to reduce fuel consumption in a parallel hybrid electric vehicle and the results were obtained for the New European Driving Cycle.

City-Bus-Route Demand-based Efficient Coupling Driving Control for Parallel Plug-in Hybrid Electric Bus

Recently,plug?in hybrid electric bus has been one of the energy?e cient solutions for urban transportation. However,the current vehicle e ciency is far from optimum,because the unpredicted external driving conditions are di cult to be obtained in advance. How to further explore its fuel?saving potential under the complicated city bus driving cycles through an e cient control strategy is still a hot research issue in both academic and engineering area. To realize an e cient coupling driving operation of the hybrid powertrain,a novel coupling driving control strategy for plug?in hybrid electric bus is presented. Combined with the typical feature of a city?bus?route,the fuzzy logic inference is employed to quantify the driving intention,and then to determine the coupling driving mode and the gear?shifting strategy. Considering the response deviation problem in the execution layer,an adaptive robust controller for electric machine is designed to respond to the transient torque demand,and instantaneously compensate the response delay and the engine torque fluctuation. The simulations and hard?in?loop tests with the actual data of two typical driving conditions from the real?world city?bus?route are carried out,and the results demonstrate that the pro?posed method could guarantee the hybrid powertrain to track the actual torque demand with 10.4% fuel economy improvement. The optimal fuel economy can be obtained through the optimal combination of working modes. The fuel economy of plug?in hybrid electric bus can be significantly improved by the proposed control scheme without loss of drivability.

串并联混合动力变速箱挡位对整车性能的影响

针对串并联混合动力车辆变速箱选型匹配问题,采用试验设计(DOE)方法选取变速箱最优速比并分析挡位对整车性能的影响。建立了整车仿真模型和控制策略并进行了台架验证,分析了该混合动力系统3种变速箱挡位配置对车辆的加速性能、爬坡性能和整车油耗的影响。仿真结果表明,挡位的增多可以提高整车动力性,降低整车对电池放电功率及电池容量的需求,但是对整车油耗改善较小。进一步仿真结果表明,即使改善发动机低转速中高负荷区域的燃油消耗率,变速箱挡位数对整车油耗的影响也不大。

复合驱动并联机构的动力学建模与仿真分析

针对一种PUU-2PRRS 5自由度复合驱动并联机构的刚体动力学建模问题,采用拉格朗日法结合虚功原理建立刚体动力学模型并进行仿真分析。首先,在考虑存在次闭环的情况下,采用闭环矢量法对并联机构进行运动学分析,推导出机构各构件质心的线速度和角速度;其次,采用拉格朗日法结合虚功原理建立复合驱动并联机构的刚体动力学模型,为复合驱动并联机构驱动力的求解及后续动力学仿真分析奠定了基础;最后,基于MATLAB软件和ADAMS软件对该并联机构进行动力学仿真分析,在给定相同末端轨迹的情况下,对比两种软件得到的驱动力变化曲线,仿真结果验证了所建动力学模型的正确性。文中不仅为PUU-2PRRS 5自由度复合驱动并联机构控制系统的搭建打下了基础,也为其他复合驱动并联机构的动力学建模分析提供了理论依据。

混合动力汽车系统效率的影响因素

为了在混合动力汽车(HEV)设计及应用中合理地分配及使用车载能源,对HEV几个效率影响因素进行了研究。通过对比计算和仿真,对几种结构方案及控制策略的适用性作了评价,并分析了双动力源连接方式、混合比、循环工况和控制策略等因素对系统效率的影响。分析结果表明:使用行星架作为输出轴、增大混合比、借助于模糊逻辑控制有利于提高车辆在循环工况(特别是市区工况)下的效率。

基于模糊在线识别的并联混合动力客车自适应控制策略

针对一款并联混合动力客车提出了一种基于模糊在线识别的自适应控制策略.基于自主研发的混合动力车数据采集监控系统构建符合本地车辆实际行驶道路特点的典型工况,设计模糊工况识别算法对车辆实际行驶的工况类型进行在线识别.根据最小等效燃油消耗控制算法和电池电量平衡控制方法,结合工况识别的结果调用相应最优控制参数,对发动机和电池的功率分配进行实时优化计算,实现对整车的控制.实验结果表明,所设计的模糊识别方法能够较好地完成行驶工况类型的识别.基于此所提出的自适应控制方法能够在满足车辆需求功率和电池SOC维持在有效工作区间内的前提下完成发动机和电池的最优功率分配,显著提高整车的燃油经济性.

并联混合动力汽车模式切换过程的协调控制

结合解放牌混合动力城市客车的实车调试,对不同模式之间的切换过程进行了分析,针对其切换过程易导致转矩波动,提出了基于电机辅助的协调控制策略,并利用AVL/Cruise及MATLAB联合仿真平台进行了建模仿真研究。仿真结果表明,协调控制策略保证了模式切换过程中动力传递的平稳性。

基于动态规划算法的混联混合动力汽车控制策略

针对某混联型混合动力汽车的布置形式,构建了整车控制数学模型。利用动态规划方法,提出了以控制整个循环发动机燃油消耗最低和电池SOC维持在理想值为目标的优化函数。提出了动态限制SOC区域模型。设计了动态规划全局搜索算法。进行了换档逻辑的优化。仿真对比了基于功率跟随的混联汽车控制策略、动态规划方法以及改进的功率跟随策略。结果显示,动态规划方法可以作为其他控制策略的评价参考,可以改善功率跟随控制策略控制效果。

基于模糊控制的并联式混合动力汽车制动控制系统

在分析和比较混合动力电动汽车(HEV)不同制动控制策略的基础上,提出了一种新的制动控制策略。在MATLAB/Simulink环境下搭建了制动系统控制模型。考虑到能量回收制动力矩和总制动力矩的连续变化,采用模糊控制策略对液压制动力矩进行动态调整。能量回收制动力矩和液压制动力矩在该控制策略下能够协同工作。仿真结果证明该控制策略有效,鲁棒性好。

并联式混合动力汽车(PHEV)动态协调控制方法硬件在环仿真

在指出并联式混合动力汽车(Parallel hybrid electric vehicle,PHEV)发动机与电动机动力耦合过程中存在的协调问题基础上,提出基于模型匹配控制的动态协调控制方法,开发出双驱动电动机结构的硬件在环仿真试验平台硬件系统和基于Matlab/Simulink/RTWT与Visual C++环境的软件系统,并建立PHEV动态协调控制方法硬件在环仿真试验台。对所设计的动态协调控制方法进行硬件在环仿真试验,试验结果表明,该动态协调控制方法能有效控制两个动力源的动力耦合过程,具有较高的转矩控制精度和很好的动态响应特性。

基于工况识别的混合动力汽车动态能量管理策略

针对固定循环工况下所制定的混合动力汽车能量管理策略存在一定局限性问题,从ADVISOR软件中选取覆盖车辆实际行驶工况的20个典型循环工况,以整车综合燃油消耗和动力电池寿命为综合优化目标,利用粒子群算法对各工况下能量管理策略中所涉及的关键参数进行了优化,并将得到的优化结果建立数据库,提出了基于行驶工况识别的混合动力汽车动态能量管理策略。最后,通过选择某个随机工况对所制定的能量管理策略进行仿真。结果表明:所制定的动态能量管理策略与未采用工况识别的能量管理策略相比,车辆综合燃油消耗下降10.70%,动力电池温升和平均有效工作电流分别下降2.46℃和1.63 A。

混合动力汽车下坡辅助控制方法

为减轻混合动力汽车(Hybrid electric vehicle,HEV)下坡过程中驾驶员的驾驶负担,提高车辆运行的安全性和经济性,提出一种满足驾驶员主观意图、确保下坡安全性和提高制动能量回收性能的下坡辅助控制(Down-hill assist control,DAC)方法。上层根据车辆下坡行驶过程中安全性需求,以满足驾驶员的主观驾驶意图为原则,提出下坡辅助控制启动和退出策略,并制定辅助控制的目标。中层依据辅助控制目标,利用比例积分微分(Proportional integral derivative,PID)方法计算总需求制动转矩,根据总制动转矩、各制动系统的制动能力和制动原理,提出电机单独制动、电机-发动机联合制动及电机-发动机-液压联合制动的转矩分配策略。下层针对电机、发动机和液压系统响应特性的不同,提出发动机接入过程的动态协调控制策略与液压转矩变化过程的动态协调控制策略。进行实车验证,结果表明该方法在减轻驾驶员的操纵负担、提高混合动力汽车下坡路段安全性的同时,能降低油耗,并改善舒适性。

基于CVT的混联式电动汽车动力切换平稳性研究

针对四轮驱动越野车提出了一种基于金属带式无级自动变速器(CVT)的混联式结构,其动力切换平稳性是这种混联式电动汽车必须解决的关键技术之一。通过发动机、电机、离合器和CVT的协调控制可以使系统在驾驶员发出加速命令时快速响应以及在模式切换时平稳,这将保证驾驶员在车辆切换过程中没有异常感觉。

并联式混合动力汽车能量管理的马尔可夫决策

为研究同轴并联式混合动力汽车的能量管理策略,建立了同轴并联式动力系统动态方程,分析了转矩需求无后效性的马尔可夫特性.在维持电池容量不变的条件下,以燃油消耗最小为优化目标,采用马尔可夫决策实施能量管理策略,并采用策略迭代方法求解了马尔可夫能量管理的转矩决策过程,在J1015工况和昆明工况进行了仿真,实现了能量管理的在线实施.结果表明,与基于动态规划的能量管理策略相比,马尔可夫决策的能量管理策略能在线实施,且电池容量变化更为平稳;在燃料消耗方面是全局次优的,在J1015行驶工况下100 km燃油消耗增加了1.32 L,在昆明行驶工况下100 km燃油消耗增加了1.59 L.

基于模型匹配控制的PHEV动态协调控制方法

在分析发动机与电动机的动态响应特性基础上,设计基于模型匹配控制的整车动力系统动态协调控制方法,并在所建立的并联式混合动力汽车(PHEV)的前向仿真模型上对该方法进行研究,证明该方法能有效控制2个动力源的动力耦合过程,具有较高的转矩控制精度和很好的动态响应特性,并利用所建立的硬件在环仿真试验台对该方法进行试验验证。

并联混合动力电动汽车动态协调控制策略及仿真研究

并联混合动力汽车在发动机和电动机工作过程中,需要根据路况进行能量分配和工作模式切换。以并联混合动力汽车在状态切换过程中总转矩不发生大的波动为控制目标,提出"转矩预分配+发动机调速+发动机动态转矩估计+电动机转矩补偿控制"的动态控制策略。以MATLAB为仿真平台,搭建了基于整车动态控制的仿真模型,对上述基本控制算法进行了定工况和全工况仿真验证。结果表明,在各种状态切换过程中,动态控制算法能有效控制混合动力系统的转矩波动,保证动力传递的平稳性。

并联混合动力汽车扭矩协调控制策略仿真研究

对于使用机械式自动变速器(AMT)的并联式混合动力汽车(PHEV),能量管理策略的实现需要对发动机、电机以及离合器和变速箱进行协调控制,为此,建立一个分层控制系统来管理整车的能量分配和实现整车的能量分配策略。能量管理策略的实现层以改善车辆行驶平顺性和减小离合器磨损为目标,协调控制动力和传动系统,实现能量管理层需要的扭矩分配、工作模式切换以及换档等要求。在Matlab/Simulink环境下建立了并联式混合动力汽车动力传动系统的仿真模型,通过仿真进行控制策略的辅助设计并验证了控制策略。当前开发的控制策略已经应用于实车,试验结果表明了控制系统和控制策略的适用性。

并联混合动力汽车从纯电动切换至发动机驱动的控制研究

阐述了混合动力汽车的发动机调速方法,通过建模、dSPACE AutoBox对系统的控制以及AVL测功机对系统的监控,完成了发动机起动、调速及离合器接合与分离的控制,建立了用电机补偿发动机动态转矩相对稳态转矩下降的转矩控制策略。动态控制与稳态控制2种试验结果对比表明,动态控制方法提高了驱动模式的切换性能与效果,可提高整车驾驶性、舒适性和耐久性。