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61.
Lei Xu 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2017,55(3):427-448
The vehicle–track coupled system has a random nature in the time–space domain. This paper proposes a computational model to analyse the temporal–spatial stochastic vibrations of vehicle–track systems, where the vehicle–track system is divided into a vehicle subsystem, track subsystem, and interfacial subsystem between the wheel and rail. In this model, the time-varying randomicity of dynamical parameters of the vehicle system, correlation, and randomness of the track structural parameters in the time–space joint dimensions, and randomness of the track random irregularities are considered. A probability dimension-reduction method was used to randomly combine different random variables. Furthermore, the probability density evolution method was applied to solve the delivery problem of probabilities between excitation inputs and response outputs. The temporal–spatial stochastic vibrations of the vehicle–track system with different coefficients of variation were studied, in which we assumed that the dynamic parameters obeyed the normal distribution, and the stochastic simulation method of the track random irregularities is probed into. The calculated results from this model are consistent with the actual measured results and physical conceptions. Thus, the temporal–spatial stochastic evolutionary mechanism can be explored, and the limits of dynamic indices can be formulated by using this developed model. 相似文献
62.
Takao Kobayashi Etsuo Katsuyama Hideki Sugiura Eiichi Ono Masaki Yamamoto 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2017,55(1):104-120
Driving force distribution control is one of the characteristic performance aspects of in-wheel motor vehicles and various methods have been developed to control direct yaw moment while turning. However, while these controls significantly enhance vehicle dynamic performance, the additional power required to control vehicle motion still remains to be clarified. This paper constructed new formulae of the mechanism by which direct yaw moment alters the cornering resistance and mechanical power of all wheels based on a simple bicycle model, including the electric loss of the motors and the inverters. These formulation results were validated by an actual test vehicle equipped with in-wheel motors in steady-state turning. The validated theory was also applied to a comparison of several different driving force distribution mechanisms from the standpoint of innate mechanical power. 相似文献
63.
Insights into vehicle trajectories at the handling limits: analysing open data from race car drivers
John C. Kegelman Lene K. Harbott J. Christian Gerdes 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2017,55(2):191-207
Race car drivers can offer insights into vehicle control during extreme manoeuvres; however, little data from race teams is publicly available for analysis. The Revs Program at Stanford has built a collection of vehicle dynamics data acquired from vintage race cars during live racing events with the intent of making this database publicly available for future analysis. This paper discusses the data acquisition, post-processing, and storage methods used to generate the database. An analysis of available data quantifies the repeatability of professional race car driver performance by examining the statistical dispersion of their driven paths. Certain map features, such as sections with high path curvature, consistently corresponded to local minima in path dispersion, quantifying the qualitative concept that drivers anchor their racing lines at specific locations around the track. A case study explores how two professional drivers employ distinct driving styles to achieve similar lap times, supporting the idea that driving at the limits allows a family of solutions in terms of paths and speed that can be adapted based on specific spatial, temporal, or other constraints and objectives. 相似文献
64.
在对现有高压共轨高速电磁阀驱动电路进行分析的基础上,提出了一种基于电磁阀自身的自升压方式,一方面把高速电磁阀关闭时本身储存的电能回收到储能电容中,另一方面在两缸工作间隙利用电磁阀线圈作为升压电路电感对储能电容进行能量补充,保证储能电容上的电压达到一个稳定状态。电路在保证实现双电压快速驱动的同时,使驱动结束的能量得到有效回收,同时省去外接专用升压电路所需要的电感部件,减小了电源电路的体积和设计成本,并且电控单元印制线路板的电磁兼容性设计易于保证。应用该方法对某高压共轨部件高速电磁阀进行试验,匹配出驱动参数,并进行稳定性试验验证,结果表明该方法能够满足工程应用需求。 相似文献
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随着汽车逐步向智能化、网联化发展,智能网联车辆逐步进入实际应用阶段。进行智能网联车辆的通行行为优化,对提升驾驶安全性和行车效率,避免事故发生和交通拥堵至关重要。车辆在通过交叉口时将受到很多环境及运动因素的影响,而现有的通行优化模型难以准确表达各类因素共同作用下的行驶环境。为此,基于风险场理论建立由环境场和运动场组成的信号交叉口行车风险场,表征信号交叉口中每点的实时行车风险程度,从而引导车辆驶向风险值低点,并提供下一步长的位移及速度指引,实现车辆的动态轨迹优化及速度控制。典型场景下的仿真结果表明:在优化模型的控制下单车的信号交叉口通行效率明显提升,其中直行方向车辆单车平均通行效率提升最高,平均提升6.35%,通过对交叉口面积内所有车辆进行通行行为优化,交叉口通行效率提升了9.3%,这表明所建模型可以准确表达交叉口行车环境并优化车辆通行行为。研究结论可应用于自动驾驶车辆的交叉口通行控制,并为网联环境下的行车环境表达和安全驾驶控制提供模型基础。 相似文献
67.
随着汽车驾驶模拟器在道路交通仿真中的广泛应用,驾驶员对视景的逼真度也相应地提出了较高的要求。视景仿真系统作为模拟器的一个子系统,其逼真度和实时的动态显示是影响道路交通仿真的关键因素。文中介绍了高等级公路三维视景的建模过程、实现方法,以及地形的简化技术。设计成果表明,这种方法对于利用驾驶模拟器进行道路交通仿真等方面的研究是可行的。 相似文献
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