共查询到17条相似文献,搜索用时 171 毫秒
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汽车防抱死制动系统性能的研究 总被引:5,自引:0,他引:5
陆文昌 《中国安全科学学报》2005,15(11):65-68
汽车防抱死制动系统的性能直接关系到汽车的运行安全,笔者以获得汽车制动最佳效能并能自动适应路况变化为控制系统的设计目标;通过分析车轮制动的动力学原理;运用自寻最优控制理论;进行了基于路面附着系数的汽车防抱死制动系统设计。仿真实验结果表明:该控制系统能充分利用最大附着力制动、实现自动路面识别并可提高汽车制动时的操作稳定性;进而证实了基于路面附着系数的汽车防抱死制动自寻最优控制方法,相对以往的控制方法更为简单和更适合于实际应用。 相似文献
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在对全地面多轴汽车起重机进行结构分析和受力分析的前提下,着重研究了多轴汽车起重机整机、制动系统及各组成部分对整车制动安全性能的影响,并以QYU160 为例,对整车制动安全性能进行了分析计算和试验研究,两者结果相吻合。 相似文献
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徐安 《中国安全科学学报》1996,6(3):35-39
对汽车防抱制动系统中制动力矩Tb与车轮滑移率S的收敛特性和收敛区域进行探讨,指出该收敛区域恰与制动稳定区重合,从而可使车辆的制动性能得到极大的改善。同时,还进行了防抱制动系统对道路交通事故影响的分析与研究。 相似文献
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制动器是起重机重要的零部件,它对起重机械的安全运行起着重要作用.针对它的检验检测,设计了1种制动器动态制动力矩测量系统,该测量系统主要由机械结构、控制系统、数据分析系统组成.它可以对鼓式、盘式、钳盘式制动器和制动电机的动态制动力矩进行测量,通用性较强.本文对它的设计思路和工作原理进行了详细阐述,并利用2台不同型号的制动... 相似文献
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汽车辅助制动装置发展综述 总被引:3,自引:0,他引:3
刘成晔 《中国安全科学学报》2008,18(1):105-111
平均行驶速度和载重量的增加,要求车辆具有更大的制动效能,为了有效分流制动负荷常采用辅助制动系统.介绍国内外制动法规的发展和现状,排气辅助制动装置、发动机缓速器、电涡流缓速器和液力缓速器的结构、工作原理及各辅助制动装置的制动性能;比较各辅助制动装置的优缺点,有利于汽车制动技术的发展,全面提高汽车行驶安全性能;展望未来汽车辅助制动装置的两大发展趋势,一是电子控制技术在汽车制动上的应用,二是多种辅助制动装置的联合制动. 相似文献
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针对气制动防抱死制动系统(ABS)调节阀测试系统气动回路设计进行研究;根据我国的汽车生产和检测现状,在确定气动测试回路总体方案的基础上,进行主控部分、负载回路、控制回路的设计和计算,所设计的气路检测系统可用于测试8种典型的气制动元件的密封性及动静态特性,通过不同的组合能够满足每一种阀的测试需求。该气动测试回路有效解决了简单阀类测量方法的不足,满足不了生产率及测量精度要求的问题。 相似文献
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汽车ABS和转向特性 总被引:1,自引:0,他引:1
汽车制动防车轮抱死机构(ABS)的作用汽车地面制动力学表明,汽车制动时随车轮抱死程度(车轮与地面的滑移率)的提高,在制动过程中,轮胎与地面的摩擦系数会同步下降,当轮胎抱死时,将失去抗侧力,只要有一点侧向力汽车就甩尾。为克服汽车制动时造成地面附着率的下降,汽车工程师发明了车轮制动时防抱死机构即PABS系统。有人会问,汽车刹车连轮胎都不会抱死,不是会延长刹车距离吗?其实不然, 相似文献
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在对全地面轴汽车起重机进行结构分析和受力分析的前提下,着重研究了多轴汽车起重机整机、制动系统及各组成部分对整车制安全性能的影响,并以QYU160为例,对整车制安全性能进行了分析计算和试验研究,两者结果相吻合。 相似文献
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系统分析游乐设施当前的测试水平,指出游乐设施运行状态测试是当前迫切需要解决的问题,并确定了加速度测试、速度测试、应力应变测试作为游乐设施运行状态测试系统的核心。结合游乐设施运行的特点,分别对以上3种核心测试技术从理论分析、设备选择、测试方法上进行了深入的研究。测试案例表明:基于以上技术测试的游乐设施运行状态测试系统是可行的,并为游乐设施检测提供了有力的技术支持。 相似文献
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刘仁生 《中国安全科学学报》2005,15(4):29-32
笔者以矿井提升机制动系统的制动器为研究对象,采用计算机仿真对其进行模拟。首先,对制动器的闸瓦位移和油压关系建立了数学模型;然后,通过计算机仿真模拟出位移-时间和油压-时间图,通过对系统的仿真可以直观地了解系统的工作性能,比如改变参数后系统的输出与实际是否相符,以使系统达到最优。仿真模拟的重点是模拟制动器的工作过程,当设定仿真参数与实际制动系统的参数相同时,检查仿真输出是否由于实际的输出一致,从而可以更有利于系统的改进和完善;同时在测试曲线中可以得到制动盘的偏摆、空动时间、闸瓦间隙等参数,这些都是影响制动器安全的重要因素,也是制动系统性能测定的重要内容。 相似文献
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This paper presents and tests an integrative model of voluntary learning behavior. Drawing on social exchange theory, we argue that individuals are more likely to pursue learning activities when they identify with their employing organization and have a high quality leader–member exchange (LMX) relationship with their supervisor. We further argue that organizational identification is enhanced by both distributive and procedural fairness, whereas LMX quality is enhanced by interpersonal and informational fairness. Moreover, we contend that effective learning behavior improves job performance. The model was tested with a sample of 398 employees from a large automobile dealership. Results supported most predictions. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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潘相晨 《中国特种设备安全》2014,(6):24-26
电梯制动器是电梯重要的安全部件,因电梯制动性能不足,而造成的电梯事故屡有发生。但电梯制动器制动力并不是决定电梯制动性能的唯一因素,本文依据标准对电梯制动器制动性能的要求,通过建立简单的数学模型,对影响电梯制动性能的因素进行了分析。 相似文献
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Explosion isolation systems provide critical protection for interconnected vessels and work areas, preventing the spread of explosions through interconnecting pipes and ducts. These systems not only prevent propagating events, but also mitigate the elevated explosion hazards of interconnected vessels, related to pressure piling and enhanced turbulence. Explosion isolation systems can, however, fail catastrophically when they are not properly designed for a use case.Evaluating the performance of explosion isolation systems includes assessing their pressure resistance, flame-barrier efficacy, and determining appropriate installation distances, which typically requires extensive testing. To predict the performance of a system for use cases outside the tested conditions, models are needed to reliably predict both the explosion dynamics and the isolation system response.In this study, a physics-based model for explosion dynamics in vented vessel-pipe systems is developed and validated. An extensive series of large-scale validation experiments were conducted, including tests using an 8 m3 vessel with attached pipes, varying the pipe dimensions, ignition location, and mixture reactivity. The model accurately captures the effects of experimental parameters and predicts the time available for isolation systems to form a flame barrier. This model can help to predict installation distances and reduce the number of tests needed to comprehensively evaluate explosion isolation systems and their use cases. 相似文献
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Objective: Though autonomous emergency braking (AEB) systems for car-to-cyclist collisions have been under development, an estimate of the benefit of AEB systems based on an analysis of accident data is needed for further enhancing their development. Compared to the data available from in-depth accident data files, data provided by drive recorders can be used to reconstruct car-to-cyclist collisions with greater accuracy because the position of cyclists can be observed from the videos. In this study, using data from drive recorders, the performance and limitations of AEB systems were investigated.Method: Data of drive recorders involving taxi-to-cyclist collisions were collected. Using the images collected from the drive recorders of those taxis, 40 cases of 90° car-to-cyclist intersection collisions were reconstructed using PC-Crash. Then, the collisions were reconstructed again utilizing car models with AEB systems installed while changing the sensor’s field of view (FOV) and the delay time of initiating vehicle deceleration.Results: The angle of FOV has a significant influence on avoiding car-to-cyclist collisions. Using a 50° FOV with a braking delay time of 0.5?s resulted in avoiding 6 collisions, and using a 90° FOV resulted in avoiding an additional 14 collisions. Even when installing an ideal AEB system providing 360° FOV and no delay time for braking, 8 collisions were not avoided, though the impact velocities were reduced for all of these remaining collisions. These collisions were caused by the cyclists’ sudden appearance in front of cars, and the time-to-collision (TTC) when the cyclists appeared was less than 0.9?s.Conclusion: The AEB systems were effective for mitigating collisions that occurred due to driver perception delay. Because cyclists have a traveling velocity, a wide-angle FOV is effective for reduction of car-to-cyclist intersection collisions. The reduction of delay time in braking can reduce the number of collisions that are close to the braking performance limit. The collisions that remained even with an ideal AEB system in the PC-Crash simulation indicate that such collisions could still occur for autonomous cars if the traffic environment does not change. 相似文献