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针对四轮独立驱动汽车在转向和变速行驶中各车轮输出转矩和功率变化规律问题,建立自然坐标系下的整车动力学模型,考虑车辆转向时的轴荷转移,并在Matlab/Simulink环境下对低速行驶的工况进行仿真。结果表明,在低速转向和变速工况行驶中,各轮的输出转矩和功率有所不同,但与理论变化趋势相吻合,进一步为各轮转矩控制策略的研究奠定基础。 相似文献
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目前,电动汽车研制的难点之一是传统电动机的转矩不够大,不得不使用变速机械来满足电动汽车起动和爬大坡的大转矩需求。本技术方案就是使用高于传统电动机常规电压的宽范围系列阶梯电压来驱动特制的轮毂电机车轮动力系统,以彻底解决当前研制电动汽车的这一难点,从而使现代电动汽车能早日大量使用,造福于人类。 相似文献
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基于对机电控制无级变速器工作原理的分析,提出电动汽车搭载机电控制无级变速器的结构方案,并相应地建立了电机数值模型、电池充电数学模型和机电控制无级变速器速比控制模型。综合考虑电机效率、机电控制无级变速器效率、电池荷电状态和整车特性,提出了再生制动时机电控制无级变速器的变速策略。在MATLAB/Simulink仿真平台上,搭建了系统再生制动性能仿真模型,并对搭载机电控制无级变速器的电动汽车再生制动性能进行了仿真。结果表明,采用所提出的变速策略与传统两挡变速策略相比,能更好地发挥电动汽车性能,提高再生制动过程中的能量回收率。通过台架试验,验证了仿真结果的有效性。 相似文献
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四轮独立转向驱动汽车相比传统车辆具有更多控制自由度,具备在高曲率跟踪精度好,低附着路面操纵稳定性优越的特点。本文针对车辆在轨迹跟踪中所面对的低附着、爆胎等紧急工况,本研究采用模型预测控制理论,针对四轮转向电动汽车的横摆稳定性问题进行了探究。以横摆角速度和横向误差为控制目标,计算出最优四轮转角和直接横摆力矩,下层采用最优转矩分配并考虑轮胎摩擦圆约束,以实现对四轮驱动电动汽车的稳定性控制。在CarSim/Simulink联合仿真整车模型中,采用参数化建模设置整车参数。通过双移线爆胎工况仿真实验分析,所提出的策略能够有效地提高四轮驱动电动汽车的轨迹跟踪精度,从而提高整车的行驶稳定性。 相似文献
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电动轮驱动的汽车取消了机械式差速器后,在转向行驶、路面不平及车轮半径不等3种工况下,会出现差速问题。文章进行了实车转向行驶试验和车轮半径不等时的差速试验,验证了对电动轮电机控制按转矩模式控制而转速随动以实现自适应差速的控制策略。电动轮控制器可以实现很好的差速性能,说明采用转矩控制和转速随动的策略是解决汽车电子差速问题的前提和关键。 相似文献
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In this paper, the torque and power required by dual motors for electric tracked vehicle during dynamic steering maneuvers with different steering radiuses are analyzed. A steering coupling drive system composed of a new type of center steering motor, two Electromagnetic (EM) clutches, two planetary gear couplers, and two propulsion motors is proposed for the dual motors drive high speed electric tracked vehicle (2MHETV), which aims to improve its lateral stability. An average torque direct distribution control strategy based on steering coupling and an optimization-distribution-based close-loop control strategy are designed separately to control the driving torque or regenerative braking torque of two propulsion motors for vehicle stability enhancement. Then models of the 2MHETV and the proposed control strategy are established in Recudyn and Matlab/Simulink respectively to evaluate the lateral stability of dynamic steering for the 2MHETV with different steering radiuses on hard pavement.The simulation results show that the lateral stability of the 2MHETV can be significantly improved by the proposed optimization-distribution-based close-loop control strategy based on steering coupling system. 相似文献
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针对分布式驱动车辆转向工况在低速下期望提高转向机动性能,高速下期望保证行驶稳定性的需求,充分考虑转向行驶内外侧车轮的转向关系以及车辆动力学,制定了适应车速变化的四轮转矩分配策略,建立了四轮轮毂电机驱动模型以及二自由度参考模型。为了改善分布式驱动转向机动性能,建立自抗扰控制器调整内外侧车轮转矩,形成合理的转速差,减小转向半径,以提高转向机动性;对于高速转向行驶稳定性的需求,通过二次规划方法优化分配各车轮驱动力矩,分析轮胎纵横向附着裕度建立目标函数,并加入附加横摆力矩和路面附着力的限制,进行车轮驱动转矩的在线优化分配,提高车辆转向行驶的稳定性;另外为避免2种控制模式转换时驱动转矩突变,根据车速和稳定性参数制定模糊规则决策2种模式的协调系数,保证2种控制模式的平滑过渡。基于CarSim和MATLAB/Simulink进行联合仿真,并搭建硬件在环平台进行试验,对所提出的方法进行验证。结果表明:在低速转向工况下,提出的分配策略能够调节内外侧车轮产生差速效果,与转矩平均分配的策略相比,转向半径有所减小,提高车辆机动性;高速转向工况下,分配策略能够保证车辆稳定转向,与未考虑稳定性控制的分配策略相比,能更好地跟踪目标轨迹,且横摆角速度控制在参考横摆角速度附近,证明了所提控制策略的有效性。 相似文献
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Wei Liu Fengchun Sun Jiangyi Lv 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2017,55(5):601-625
This paper describes an integrated chassis control framework for a novel three-axle electric bus with active rear steering (ARS) axle and four motors at the middle and rear wheels. The proposed integrated framework consists of four parts: (1) an active speed limiting controller is designed for anti-body slip control and rollover prevention; (2) an ARS controller is designed for coordinating the tyre wear between the driving wheels; (3) an inter-axle torque distribution controller is designed for optimal torque distribution between the axles, considering anti-wheel slip and battery power limitations and (4) a data acquisition and estimation module for collecting the measured and estimated vehicle states. To verify the performances, a simulation platform is established in Trucksim software combined with Simulink. Three test cases are particularly designed to show the performances. The proposed algorithm is compared with a simple even control algorithm. The test results show satisfactory lateral stability and rollover prevention performances under severe steering conditions. The desired tyre wear coordinating performance is also realised, and the wheel slip ratios are restricted within stable region during intensive driving and emergency braking with complicated road conditions. 相似文献
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电子控制液压动力转向技术是通过对传统的液压动力转向器的控制阀进行改造,增加一套通过电子控制的电动旁通阀,根据车速和方向盘的转角,控制进入转向器工作缸的助力油,从而改善车辆在高速时转向器的助力特性。本文主要介绍了电子控制液压助力转向器的组成﹑原理及特点,及其在混合动力客车上应用。 相似文献