四轮驱动混合动力轿车驱动防滑控制研究

多动力源增加了混合动力汽车驱动轮转矩的调节方式,也对依赖常规防抱死制动系统(Anti-lock braking system,ABS)而实施的驱动防滑控制(Acceleration slip regulation,ASR)带来新的挑战.针对四轮驱动混合动力轿车,考虑非线性7自由度车辆纵向动力学,建立样车动力系统前向仿真模型.利用转矩控制精确且响应快的电动机进行打滑车轮的转矩调整,基于既有并经验证的能量管理策略,开发逻辑门限及P-Fuzzy-PI多模态分段ASR控制算法,结合低附着系数路面纯电动起步及混合驱动急加速行驶工况进行离线仿真.通过整车电控单元(Hybrid control unit,HCU)引入前轮轮速传感器信号并集成ASR功能,在冰雪路面开展实车纯电动起步防滑试验.仿真及测试结果表明,所设计的两种ASR控制策略均能有效地抑制驱动轮的瞬时打滑,基于能量管理策略开发ASR控制算法并通过HCU来实施是可行且有效的.     

基于滑模变结构控制的多轮独立电驱动车辆驱动防滑控

车辆在低附着路面起步或加速时,车轮极易发生滑转,严重影响车辆行驶动力性和稳定性。针对多轮独立电驱动车辆的驱动防滑控制问题,基于滑模变结构控制理论,设计了防滑控制算法,并设置平滑切换函数,减小转矩切换引起系统输出的抖振,通过滑模变结构控制器调节电机转矩,使车轮滑转率跟踪最优滑转率。在ADAMS/View与MATLAB/Simulink中分别建立车辆动力学模型和防滑控制器模型。机电联合仿真实验结果表明:该控制算法能够在车辆起步阶段或加速行驶时有效控制车轮滑转率,达到了提高车辆动力性的目的。     

基于路面识别的电动汽车驱动防滑控制策略研究

针对电动汽车在低附着路面行驶时驱动轮滑转问题,对后轮独立驱动电动汽车进行了驱动防滑控制研究,提出了基于模糊路面识别的自适应模糊PID控制方法,提高汽车在极限工况下车辆的稳定性。首先根据轮毂电机转矩、转速易于测得的优势,设计了基于Burckhardtμ-S模型的模糊路面识别算法。根据车辆运动状态,路面识别算法对当前路面和最优滑转率进行辨识。然后采用自适应模糊PID控制器将驱动轮滑转率实时控制在最优滑转率附近。最后选择典型工况,基于Car Sim与Matlab/Simulink联合仿真实验对控制方法进行了验证。仿真结果表明,该模糊路面识别算法能够较好识别路面附着系数和其最优滑转率;基于路面识别的驱动防滑控制具有良好的控制效果,提高了极限工况下车辆的稳定性与动力性。     

四轮轮毂电机驱动电动汽车驱动防滑控制关键技术综述

驱动防滑控制是四轮轮毂电机驱动电动汽车主动安全控制关键技术之一。分别从车速估计方法、路面识别方法、驱动防滑控制算法三个方面综述了四轮轮毂电机驱动电动汽车驱动防滑控制的关键技术与难点。通过比较车速估计方法中基于运动学和基于动力学的估计方法的优缺点,明确了基于多方法、多信息融合的估计方法是提高车速估计精度的重要措施。比较了基于试验与基于模型的路面识别算法,分别对路面识别中涉及的路面附着系数估计方法、路面类型识别方法进行了分析,并指出:基于试验的路面识别方法仍需提高对测试环境的鲁棒性,基于模型的识别方法则需提高轮胎模型精度以及不同工况的自适应性。总结了基于滑转率控制和基于电机输出转矩控制的驱动防滑控制策略,对现有驱动防滑控制算法进行了分析,并指出提高算法的适应性和鲁棒性是未来的研究重点。最后对四轮轮毂电机驱动电动汽车驱动防滑关键技术发展方向进行了展望。     

电动车驱动防滑控制策略研究

针对驱动轮在附着条件恶劣的路面行驶时滑转问题,对后轮独立驱动电动汽车进行驱动防滑控制研究。提出了基于自适应模糊神经网络控制的驱动防滑控制策略,提高汽车在极限工况下车辆的稳定性。根据车辆运动状态,路面识别算法对当前路面和最优滑转率进行辨识。采用自适应模糊神经控制器将驱动轮滑转率实时控制在最优滑转率附近。仿真结果表明:模糊路面识别算法能够较好识别路面附着系数和其最优滑转率;基于自适应模糊神经控制的驱动防滑具有良好的控制效果,提高了恶劣路面行驶时车辆的稳定性与动力性。     

分布式后驱电动客车驱动防滑系统设计及验证

针对分布式驱动电动客车在低附着路面等工况下驱动打滑问题,对两后轮采用轮毂电机驱动的电动客车的驱动防滑控制及测试进行了研究,提出了一种包括滑转率估算、单轮驱动防滑、双轮转矩协调模块的驱动防滑系统。通过左转及右转两种工况下的实车试验与仿真结果对比分析的方法,验证了搭建的分布式后驱电动客车模型的准确性;基于Truck Sim与Matlab/Simulink联合仿真平台,在分布式后驱电动客车模型上对设计的驱动防滑系统进行了对接路面及对开路面下的仿真验证。研究结果表明:该驱动防滑系统可以有效地控制分布式后驱电动客车在低附着路面上的驱动打滑情况;特别在对开路面上,所设计的协调控制模块在实施单轮驱动防滑后,通过协调控制左右轮转矩,能较好地抑制非期望横摆力矩的产生,使车辆能够稳定行驶。     

应用Simulink铰接式车辆牵引力模糊控制建模分析

在车辆运行中,根据不同路面运行状况对牵引力输出进行合理控制,既可提高车辆动力性,又能减小机构之间的冲击和磨损,提高整体寿命。针对铰接式电动轮车辆,采用牵引力控制系统,对车辆运行中的滑转率进行监测,使用模糊控制系统对牵引力进行控制,从而有效控制电机的输出转矩,以实现不同运行路面滑转率的有效控制。搭建铰接式电动轮车辆的整车动力学模型,对转向过程中的动力学方程进行分析;并搭建电机控制模型和适合本系统的牵引力模糊控制器;基于Matlab/Simulink将模糊控制器与整车模型集成整车牵引力模糊控制分析模型,对低附着系数路面、对开路面、高低附着系数对接路面的整车运行状况进行分析。由分析结果可知:车辆在不同附着系数运行时,滑转率模糊控制系统有效减小车轮的打滑程度,使得路面提供的附着力得到最大程度的利用,保证车辆行驶稳定性,提高行车安全性,控制取得很好的效果;分析方法和分析结果为此类研究提供参考。     

四轮独立驱动电动汽车直驶稳定性协调控制研究

针对四轮独立驱动电动汽车直线行驶跑偏及行驶稳定性问题,提出驱动转矩协调控制策略。该策略采用分层控制逻辑,上层控制逻辑层负责车速跟随控制、附加横摆力矩计算、驱动防滑控制;下层控制逻辑层负责驱动转矩协调分配。基于车辆动力学软件Carsim和MATLAB/Simulink搭建四轮独立驱动电动汽车协调控制系统仿真模型,在高附着、低附着和对开路面等典型工况进行仿真,结果表明,相比于转矩平均分配及无控制,协调控制策略使车辆横摆角速度保持在0±0.05(°)/s,且车轮滑转率控制在最优滑转率范围内,提高了车辆直驶稳定性。     

双电机后驱车辆操纵稳定性分层混杂模型预测控制

为改善车辆在复杂工况下的操纵稳定性,解决低附着路面易失稳的问题,针对后驱双电机轮边驱动电动汽车提出一种结合直接横摆控制与主动转向控制的操纵稳定性控制策略。控制策略采用分层控制结构：上层控制器采用多输入多输出系统的模型预测控制,对目标附加横摆力矩与前轮主动转向角进行求解;下层转矩分配控制器采用混杂模型预测控制（hMPC）,将轮胎纵向力的非线性特征简化为分段的混杂系统,在分配驱动转矩时考虑车轮在不同工况下的滑转情况。搭建了基于dSPACE实时仿真系统的仿真平台,在高附着、低附着路面下进行半实物仿真试验。仿真结果表明,与二次规划（QP）转矩分配算法相比,高附着路面工况下平均相对误差减小了17.64%,方均根误差减小了42.86%,最大偏离误差相对减少了7.64%;低附着路面工况下可以有效防止车辆失稳,改善操纵稳定性。     

多轴商用车驱动防滑硬件在环试验研究

以三轴商用车ASR为研究对象,研究了低附路面下发动机扭矩控制和分离路面下差动制动控制的驱动防滑控制算法,设计了发动机扭矩PID控制器和以滑转量和轮加速度为门限的差动制动门限逻辑控制算法,并研制了ABS/ASR控制器。采用Trucksim、Labview RT及转向、制动系统实物搭建硬件在环仿真平台,对开发的ABS/ASR控制器进行典型工况试验分析。试验结果表明:所开发的驱动防滑控制算法能较好地抑制车轮滑转,提高了车辆动力性和燃油经济性。     

Development of TCS slip control logic based on engine throttle control

Slip control systems are used to prevent wheel slipping and to improve acceleration performance, stability and steerability on slippery roads through the engine torque and/or brake torque control. This paper mainly deals with the engine control algorithm via adjustment of the engine throttle angle. The slip control algorithm developed in this research includes a control gain scheduling part and a road estimating part to enhance control performance. Various actual vehicle tests have been carried out on low friction roads in order to verify the developed slip control algorithm. The test results show that the controlled vehicle is superior to the non-controlled vehicle in acceleration performance and stability.     

Clutch torque formulation and calibration for dry dual clutch transmissions

This paper focuses on the clutch torque formulation and calibration for dry dual clutch transmissions (DCT). The correlation on the theoretical clutch torque and control parameters is established based on constant friction power and clutch actuator kinematics. An algorithm based on powertrain dynamics is proposed for the calculation of clutch torque during vehicle launch and shift operations. This algorithm uses wheel speed sensor data as input and is capable of determining the clutch torque while both clutches are slipping, thus provides a reliable correlation between clutch torque during real time operations and clutch actuator control variables. The accuracy of the proposed algorithm has been validated by torque measurement in prototype testing on prove ground.     

干式DCT双离合器联合起步最优协调控制

基于自主开发的6速干式双离合器自动变速器(Dual clutch transmission, DCT),提出基于极小值原理的双离合器联合起步过程发动机和双离合器转矩协调最优控制算法。在起步滑摩阶段,以滑摩功和冲击度为性能指标,在反映驾驶员意图的终端约束下,采用极小值原理和改进的发动机恒转速控制,研究并确定起步过程中双离合器,发动机转矩及其转速。根据起步控制目标,确定分离离合器分离条件和离合器的转矩分配关系。在需求转矩切换阶段,将发动机输出转矩平滑切换到驾驶员需求转矩。在Matlab/Simulink软件平台上,搭建DCT车辆双离合器联合起步控制仿真模型,对不同驾驶意图和起步档位下DCT车辆的起步过程进行仿真。结果表明,所提出的基于极小值原理的发动机和双离合器转矩协调控制策略,有效地保证双离合器联合起步品质,反映起步意图,延长离合器使用寿命。将所得的离合器最优转矩控制律转化为离合器位置控制律,在离合器伺服控制试验台架上进行离合器位置闭环控制,得到较好的跟踪效果。     

轮胎稳态运动学与六分力预报Ⅰ:理论与方法

提出一种新的轮胎运动学描述和六分力预报理论。滚动接触是汽车轮胎力学、轮轨动力学的核心问题,由于涉及刚体转动与有限变形,滚动接触运动学与动力学的描述与求解非常困难。用拉格朗日—欧拉混合描述法分析大变形滚动接触结构的速度场、加速度场和接触变形。以车轮定位角为卡尔丹角,用拉格朗日描述,得到了包含刚体转动和弹性变形的轮胎速度场。而接触区域的变形和受力用欧拉描述,通过欧拉网格和拉格朗日网格的信息传递,完成滚动结构动力学分析。所提出的理论可以退化到Fiala模型,并可以从理论上解释子午线轮胎的伪侧偏和伪侧倾现象。基于所建立的运动学理论和非线性有限元,建立轮胎六分力预报方法。针对某轿车子午线轮胎,分析轮胎接地面滑移速度、接地面积、接地压力、侧向剪力分布等随着侧偏角的变化规律,并研究该轮胎侧偏力和回正力矩随着胎面刚度和摩擦因数的参数敏感性。结果表明轮胎侧偏刚度和回正刚度主要受结构刚度控制,而峰值侧偏力和峰值回正力矩主要受摩擦因数控制。将利用所建立的方法和试验,探讨带束层结构对大规格子午线轮胎侧偏特性的影响规律,进一步验证所提出的理论和方法的正确性。所提出的理论和方法开辟了直接从轮胎设计预报轮胎六分力的新途径。     

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.     

An investigation of energy efficiency of a wheel loader with automated manual transmission

This paper describes an investigation of energy efficiency by applying an advanced powertrain system in a conventional wheel loader. A conventional powertrain of a wheel loader consists of an engine, torque converter and transmission. A torque converter in a conventional system generally causes a significant amount of energy loss, as determined by analyzing energy flow based on V-pattern working. To prevent energy loss in a torque converter, Automated manual transmission (AMT) was proposed and modeled in this paper as an advanced powertrain. A wheel loader based on AMT does not need to use a torque converter since the single clutch system is used between the engine and transmission with subsystems of engine controller, clutch actuator and controller. A simplified single clutch system and controller were constructed for V-pattern working of a wheel loader. Additionally, a PI-controller was used as a control algorithm for engine speed control to prevent energy loss while the clutch is not engaged. All simulation models have been constructed in the Matlab/ Simulink environment, and simulation studies were conducted by using a simulation model of a wheel loader with a driver model based on V-pattern working. Simulation results of the AMT-based wheel loader were analyzed by comparison with the results of the torque converter-based wheel loader, and the results show that the AMT-based wheel loader is more energy efficient than the conventional wheel loader.     

A nonlinear sideslip observer design methodology for automotive vehicles based on a rational tire model

In this paper we develop a nonlinear vehicle sideslip observer design that is based on a nonlinear lateral dynamics vehicle model. In doing so we utilize a novel simplified rational tire model to compute the lateral wheel forces. This tire model is significantly simpler than the well known Magic Formula (in terms of the number of model parameters), yet it provides sufficient detail over a wide range of operating conditions for the purpose of estimating the sideslip angle. The input to the nonlinear observer are typical signals that are available within lateral stability control systems, which include vehicle speed, steer angle, lateral acceleration and yaw rate measurements. In our analysis, we assume the road friction to be a known parameter. We utilize a recent theorem from the literature and show that the suggested nonlinear state estimator a) is asymptotically stable for the case where the observer makes use of the exact tire model, b) is stable (in the sense of Lyapunov) providing uniformly bounded error dynamics for the case where it makes use the proposed rational tire model to approximate the exact tire model. Finally, we provide numerical simulations to demonstrate the efficacy of our nonlinear observer based estimation technique under varying road friction conditions.     

DCT车辆起步及换挡过程双离合器H∞鲁棒控制

根据自主研发的双离合器自动变速器（DCT）结构和工作原理,建立了DCT车辆起步及换挡过程动力学模型。考虑起步及换挡过程中发动机扭矩波动及油门踏板抖动等不确定性因素,基于Riccati不等式和线性矩阵不等式设计了H∞鲁棒控制器,分析了冲击度和滑摩功两项离合器接合性能指标,探讨了离合器最优传递扭矩的求解问题,并与线性二次型最优控制策略进行了仿真对比分析,结果表明：H∞鲁棒控制可以较好地解决DCT车辆起步与换挡过程离合器压力控制问题,并能显著地改善离合器控制的鲁棒性能。     

考虑操纵稳定性的适时四驱扭矩分配策略

以某款全新开发的电控适时四驱SUV为研究对象,为同时发挥四轮驱动(4WD)与直接横摆力矩控制(DYC)的优势,建立适应于动力性及操纵稳定性的汽车动力学系统模型,提出基于轮胎最小滑移率同时保持横摆角速度跟随的适时四驱智能扭矩分配策略,采用PID算法计算出保持车辆最小滑移率及横摆角速度跟随所需的四驱控制器控制电流并加以控制。然后将该算法移植到单片机中进行低附试验,全油门加速工况、蛇形工况及定圆加速工况试验结果表明:制定的智能扭矩分配策略在迅速抑制车轮打滑的同时能有效提升车辆在低附路面的操纵稳定性,进一步提高了车辆的主动安全性,具有较强的工程实用性。     

人-椅8自由度车辆系统的平顺性和稳定性研究

文中在Matlab/Simulink中搭建了人-椅8自由度车辆系统仿真模型,在仿真分析时考虑汽车前、后轮之间的延迟性,以路面随机信号作为输入激励,研究了汽车平顺性的时频特性,且分别通过4个轮胎的输入激励研究了汽车的稳定性.研究结果表明:路面输入为随机信号时,车身垂直加速度,车身俯仰角加速度,人-椅垂直加速度,前、后悬架...