共查询到19条相似文献,搜索用时 609 毫秒
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当车辆在均匀的路面上行驶时,车速的改变会引起路面的非平稳激励,由于车速的改变,适用于频域分析的方法已不再有效.现用状态空间模型来描述车辆在时域的动态特性.分别针对两种车辆悬架系统:四分之一车辆模型和二分之一车辆模型,采用数值计算来定量地分析加速和减速对路面动载的影响.改进的方法可用于研究路面结构的动态响应,对更好地进行路面结构设计和路面非破损检测与评价有很大的帮助. 相似文献
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《公路交通科技》2020,(8)
为研究桥面非平稳随机激励对车桥耦合系统的影响,采用滤波白噪声法生成单轮桥面非平稳随机激励时域模型,结合车辆前后轮的时间滞后和左右轮的相干关系,生成车辆六轮相关的桥面非平稳随机激励样本并验证了样本的有效性。分析一座3×30 m连续T梁桥和一辆三轴重载汽车在非平稳桥面激励下的车桥耦合振动响应,现场实测桥面不平度,并采用传统蒙特卡罗法对车辆和桥梁的振动响应进行计算。研究结果表明:根据车辆六轮间的时间滞后关系和相干函数关系所建立的桥面非平稳随机激励模型满足目标相干函数和功率谱密度,且时间滞后关系明确,模型有效可靠;当车辆加速行驶时,因桥面不平顺引起的非平稳随机激励信号的幅值随速度的增大而增大,非平稳激励下的桥梁和车辆振动响应大于平稳激励所产生的振动响应;非平稳激励对桥梁振动响应的均值影响很小,但对车辆振动响应均值影响较大,车辆振动对桥面随机激励更敏感;非平稳激励对车辆和桥梁振动响应标准差的影响较大,且振动响应标准差随着车辆加速度的提高而增大;研究车桥耦合振动很有必要考虑车辆非匀速行驶而引起的桥面非平稳随机激励,建议车辆匀速通过桥梁,尽量避免在桥上加速行驶。 相似文献
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基于8自由度的非线性车辆动理学模型,以四轮相关滤波白噪声路面为系统输入,对四轮车辆的随机振动过程进行了计算机时域模拟和实验验证,进而分析了在不同车速条件下钢板弹簧和减震器的非线性因素对车辆平顺性的影响,深入揭示了车辆非线性振动过程的本质。 相似文献
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为研究时间和空间频率路面激励下重型车辆动载特性,将车辆的轮胎、钢板弹簧视为柔体,橡胶垫块、限位块简化为具有非线性刚度和阻尼特性的力元,采用多体动力学仿真软件SIMPACK建立刚柔耦合的车辆整车虚拟样机,并采用有理函数功率谱密度的谐波叠加法建立空间域和时域路面激励数学模型,创建一个时域和空间域路面激励下车辆行驶动力学模型,仿真计算了车辆各轴轮胎的法向作用力和车轮法向动栽系数.结果表明:不同车速下,时域和空间域路面激励下得到的轮胎法向作用力的变化规律和大小均不相同,而且轮胎法向作用力最大值出现的位置也不同;中、后轴车轮法向动栽系数变化规律基本相似,但前轴车轮法向动载系数变化规律不同.研究结果可为轮胎动载荷计算、验证、预测提供参考依据. 相似文献
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利用汽车的两自由度模型,应用Simulink软件仿真分析了车速与路面不平度对车轮随机动载变化趋势的影响。同时也分析了车轮随机动载的大小对路面疲劳应力的影响,指出了不同车速和路面不平度引起的路面动力反应及损伤变化规律,即车速和路面不平度的增加将导致汽车动载的增加,从而加速路面的损伤。提出了针对路面状况调整车速可以降低车轮随机动载,从而达到减轻路面损伤的要求。 相似文献
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Optimal Control of a Vehicle Suspension Incorporating the Time Delay between Front and Rear Wheel Inputs 总被引:2,自引:0,他引:2
N. Louam D. A. Wilson R. S. Sharp 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1988,17(6):317-336
An optimal control law for a vehicle suspension is developed using a discrete linear quadratic regulator framework. The time delay between the disturbance due to the road at the front and rear wheels is incorporated into the model, and it is shown that the optimal control law requires information gathered at the front wheels. A comparison is made between the optimal control law and a suboptimal one which does not incorporate front wheel road information. 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(7):969-991
This is a theoretical investigation into the effect of various suspension configurations on a tracked vehicle performance over bump terrains. The model developed is validated using published experimental data of the modal characteristics of the vehicle. The desired performance is based on ride comfort via the mixed objective function (MOF), which combines the crest factor of bounce acceleration, bounce displacement, angular acceleration, and pitch angle. The optimisation process involves evaluating the MOF for different numbers and locations of dampers and under different rigid bump road conditions and speeds. The system responses of the selected suspension configurations in the time and frequency domains are compared against the undamped suspension. The results show that the suspension configurations have a significant effect on the vehicle mobility over bump road profiles. For a five-road–wheel half model of a tracked vehicle, the maximum number of dampers to use for ride comfort over these road bumps is three with the dampers located at wheel positions 1, 2 and 5. This confirms the current practice for many tracked vehicles with 10 road wheels. However, it is further shown that the suspension fitted with two dampers at the extreme road wheels offer the best performance over various rigid bump terrains. 相似文献
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利用计算机仿真技术预测车身零件疲劳寿命 总被引:6,自引:4,他引:6
为缩短新车开发周期、节约样本制造费用,本文提出了一种在计算机仿真环境中预测车身零件疲劳寿命的新方法。以某轻型客车为例,首先建立了该车的整体有限元模型。然后将采自试车场的典型路面谱作用于轮胎与路面 的接触点进行随机激励。不仅首次在计算机上模拟了汽车随机振动过程,而且得到了关键部位的加速度和动态应力响应及其相应的功率谱密度。最后,应用随机振动和疲劳累积损伤理论对仿真结果进行后处理,估算出该车在一定速度下连续行驶的疲劳寿命。其分析结果显示的危险部位与道路试验基本一致。 相似文献
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This paper presents a system to identify road and non-road regions from monocular color images of paved and unpaved roads. Despite being a single object, the road in these images is subject to large changes in appearance due to environmental effects and track materials. This condition has challenged the practical application of road identification. The proposed system combines random forest with color correlogram to overcome such conditions and offers a classifier for road and non-road regions in traffic images. As a color feature, the color correlogram depicts the spatial correlation of color changes in an image. Using random forest, road identification is formulated as a learning paradigm. The combined effects of color correlograms and random forest create a robust system capable of identifying roads even in variable situations in real time. This combination is more effective than other combinations, such as a color histogram plus random forest, a color correlogram plus neural network, or a color histogram plus neural network. 相似文献
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基于制动轨迹检测的汽车路试模拟技术 总被引:1,自引:0,他引:1
为提高汽车制动性能检测结果的客观性,解决对同一辆汽车进行台试与路试的检测结果不一致的问题,提出路试模拟技术.该技术得以实现的关键是汽车制动轨迹的检测,具体方法是:在单个矩形测试平板的4个角,分别安装相同的压力传感器,以矩形平板的相邻边,建立平面坐标系,当车轮在平板上制动时,利用力矩平衡原理,求得车轮制动时的运动轨迹.将测试平板并排串联放置,组成路试模拟系统,可以对汽车各个车轮的制动轨迹同时进行检测.利用该方法可实现对汽车制动距离、横向位移、航向角等参数进行实时检测,从而模拟路试法进行汽车制动性能的评价. 相似文献