共查询到19条相似文献,搜索用时 375 毫秒
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线控转向系统由于其可以自由设计传动比的特点,可以保证在不同工况下,汽车都有着良好的转向特性和操纵稳定性。文章主要对线控转向系统理想传动比进行了研究设计。在中低速段,采用基于稳态横摆角速度增益不变的设计方案;在高速段,采用模糊控制对传动比进行设计。最后通过仿真试验,验证了设计的理想传动比的控制效果。 相似文献
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在分析车身侧倾对转向系统影响的基础上,对转向系统通常采用的参考模型进行修改,并探讨了轮胎侧偏刚度和车速对参考模型横摆角速度的影响.得出结论为,轮胎侧偏刚度对参考模型的横摆角速度增益有较大影响:前轮侧偏刚度的降低使横摆角速度大致成比例地减小.利用最优前馈和反馈控制方法,提出了四轮转向变增益跟踪控制策略.采用非线性半经验轮胎模型的仿真结果表明,所提出的变增益跟踪控制策略对车辆的操纵稳定性有重大改善. 相似文献
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独立轮电驱动车辆主动操纵稳定控制研究 总被引:1,自引:0,他引:1
提出了采用变增益参考模型的滑模跟踪控制策略,以横摆角速度和侧滑速度为控制对象,独立控制左右轮驱动力产生直接横摆力矩,提高了车辆在极限工况下的操纵稳定性,并改善了车辆固有的转向特性。改进的滑模控制算法减小了系统抖振并具有较强的鲁棒性。 相似文献
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为了解决传统固定转向传动比以及鲁棒H∞控制方法无法很好地改善车辆稳定性的问题,提出全轮线控转向车辆的变传动比和可拓H∞控制策略。首先,建立八自由度车辆动力学模型和轮胎模型。其次,以车辆方向盘转角和车速为输入信息,基于模糊控制方法设计全轮线控转向车辆的转向传动比,并计算出全轮线控转向车辆的前轮转角。然后,以横摆角速度偏差和偏差微分为特征值,基于可拓控制理论将车辆状态划分为3个区域:经典域、可拓域和非域;在经典域中,采用基于横摆角速度反馈的鲁棒H∞控制方法,实时获取全轮线控转向车辆的后轮转角;在可拓域和非域中,结合可拓控制和H∞控制策略,动态调整H∞控制器的输出信号,在保证控制系统鲁棒性的前提下改善车辆的操纵稳定性。最后,基于MATLAB/Simulink仿真平台和自主研制的全轮线控转向特种消防救援车辆,通过正弦转向、单移线、阶跃转向、双移线等典型工况对所提控制方法进行验证,并以平均绝对误差和均方根误差为评价指标,与无控制和H∞控制方法进行对比分析。仿真和试验测试结果表明:①变传动比控制方法不仅可以提高车辆低速时的转向灵敏度,也能改善车辆高速时的稳定性;②相比传统鲁棒H∞控制,可拓H∞控制策略提高了全轮线控转向车辆的操纵稳定性,改善了车辆全轮线控转向控制系统的鲁棒性。 相似文献
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J. Song 《International Journal of Automotive Technology》2012,13(4):563-570
This study introduces an integrated dynamic control with steering (IDCS) system to improve vehicle handling and stability under severe driving conditions. It integrates an active rear-wheel steering control system and a direct yawmoment control system with fuzzy logic. Direct yaw-moment control is achieved by modifying the optimal slip of the front outer wheel. An 8-degree-of-freedom vehicle model was used to evaluate the proposed IDCS for various road conditions and driving inputs. The results show that the yaw rate tracked the reference yaw rate and that the body slip angle was reduced when the IDCS was employed, thereby increasing the controllability and stability of the vehicle on slippery roads. The IDCS system reduced the deviation from the center line for a vehicle running on a split m road. 相似文献
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针对轮毂电机分布式驱动越野车辆在狭小空间快速机动的需求,设计了一种分层结构的原地转向控制策略。基于动力学原理分析了各轮载荷、附着条件对原地转向横摆速度的影响机理,并搭建原地转向运动学模型,上层采用模型预测控制算法设计原地转向理想轨迹以及期望的横摆角速度,开发基于PI滑模控制的横摆运动跟踪算法,通过补偿转向横摆力矩以提高方向角控制的鲁棒性和稳定性,下层以最优轮胎利用率为目标,设计二次规划算法优化分配各轮附加横摆力矩。dSPACE硬件在环测试结果表明,所提出的控制算法可在保证稳定性的前提下实现原地转向,大幅提高了车辆的转向机动性,在方向盘动态输入仿真中,车辆最大转弯半径为0.157 m,转向中心的最大偏移量为3.610 m;同时,驾驶员能对转向过程进行闭环控制,实现了原地转向过程中横摆速度的实时调节。 相似文献
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Steffen Wagner Thomas Weiskircher Dieter Ammon Günther Prokop 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2018,56(8):1139-1161
This paper presents a new application of active rear-wheel steering control to improve the lateral vehicle behaviour. In the state of the art, yaw or lateral velocity is used as control variable that means one degree of freedom being not directly controlled. A worse subjective impressions due to movements in the rear end of the vehicle during strong counter-steering are a consequence. To avoid this effect in urban surroundings, an innovative structure to control the pivot point distance of the vehicle is proposed. In this case the coupled elementary states yaw and lateral velocity can be influenced based on a higher level criteria. Analysis show that pivot point fixing provides a comprehensible reference behaviour. Solving the issue of singularity during disappearing yaw movement is the basis to design a performant modified feedforward input–output linearisation. An analytic stability analysis of the internal dynamics shows system immanent limitations which do not influence the target of improving the lateral vehicle dynamics in urban manoeuvres. Finally, the advantages of pivot-based control are highlighted by a comparison with state of the art rear axle control. 相似文献
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There are basically two methods to control yaw moment which is the most efficient way to improve vehicle stability and handling.
The first method is indirect yaw moment control, which works based on control of the lateral tire force through steering angle
control. It is mainly known as active steering control (ASC). Nowadays, the most practical approach to steering control is
active front steering (AFS). The other method is direct yaw moment control (DYC), in which an unequal distribution of longitudinal
tire forces (mainly braking forces) produces a compensating external yaw moment. It is well known that the AFS performance
is limited in the non-linear vehicle handling region. On the other hand, in spite of a good performance of DYC in both the
linear and non-linear vehicle handling regions, continued DYC activation could lead to uncomfortable driving conditions and
an increase in the stopping distance in the case of emergency braking. It is recommended that DYC be used only in high-g critical
maneuvers. In this paper, an integrated fuzzy/optimal AFS/DYC controller has been designed. The control system includes five
individual optimal LQR control strategies; each one, has been designed for a specific driving condition. The strategies can
cover low, medium, and high lateral acceleration maneuvers on high-μ or low-μ roads. A fuzzy blending logic also has been utilized to mange each LQR control strategy contribution level in the final control
action. The simulation results show the advantages of the proposed control system over the individual AFS or DYC controllers. 相似文献
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Fuzzy-logic applied to yaw moment control for vehicle stability 总被引:6,自引:0,他引:6
B. L. Boada M. J. L. Boada V. Dí az 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2005,43(10):753-770
In this paper, we propose a new yaw moment control based on fuzzy logic to improve vehicle handling and stability. The advantages of fuzzy methods are their simplicity and their good performance in controlling non-linear systems. The developed controller generates the suitable yaw moment which is obtained from the difference of the brake forces between the front wheels so that the vehicle follows the target values of the yaw rate and the sideslip angle. The simulation results show the effectiveness of the proposed control method when the vehicle is subjected to different cornering steering manoeuvres such as change line and J-turn under different driving conditions (dry road and snow-covered). 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(10):753-770
In this paper, we propose a new yaw moment control based on fuzzy logic to improve vehicle handling and stability. The advantages of fuzzy methods are their simplicity and their good performance in controlling non-linear systems. The developed controller generates the suitable yaw moment which is obtained from the difference of the brake forces between the front wheels so that the vehicle follows the target values of the yaw rate and the sideslip angle. The simulation results show the effectiveness of the proposed control method when the vehicle is subjected to different cornering steering manoeuvres such as change line and J-turn under different driving conditions (dry road and snow-covered). 相似文献
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A. D. Dorey M. C. Good P. N. Joubert 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1980,9(1):19-44
A variable characteristic car (VCC) has been developed at Melbourne University for driverlvehicle handling research. The vehicle is unusual in that it has facilities for varying both its fixed control and free control dynamic characteristics over wide ranges. In this paper the servo systems used to effect these changes are described. The calibration methods used to relate the vehicle response characteristics to the variable servo settings are detailed. Sample calibration results are given for the fixed control parameters steering ratio, yaw response time and stability factor. Calibration of the free control parameters is also described and results are given for the steering torque gradient, and the time-to-peak and percentage overshoot of the steering wheel motion in response to a step input of torque. 相似文献