共查询到20条相似文献，搜索用时 93 毫秒
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以液压伺服阀控缸位置控制系统为研究对象,通过对液压伺服阀控液压缸系统的详细分析,建立了液压系统的动态数学模型。利用MATLAB软件对其动态模型进行仿真分析,并讨论了影响液压伺服阀控缸位置控制系统动态特性的主要因素。 相似文献
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在节流闲出口节流调速系统中,负载的变化特别是阶跃变化,液压缸两腔压力会发生动态变化,使活塞(杆)的速度产生波动,甚至引起系统中波压元件损坏,影响液压系统的正常工作.以负载作为输入,液压缸有杆腔和无杆腔压力作为输出分别建立系统的数学模型,得到了液压缸两腔压力超调量的变化规律,并利用压力传感器测量了压力超调量的变化,通过试验对理论分析进行了验证,试验数据与理论分析相吻合,利用系统液压缸两腔压力动态变化规律,修正了液压元件主参数(额定压力)选择的计算公式,为系统设计以及元件参数选择提供依据. 相似文献
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对目前汽车配置的助力转向系统做了简要比较,指出了机械液压和电子液压助力的缺点。介绍了电动助力转向系统的构成、工作原理以及主要设计参数和控制特性。 相似文献
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介绍了汽车转向系统的功用,在分析机械转向系统、液压动力转向系统、电控液压动力转向系统、电动助力转向系统、线控转向系统特点的基础上,着重阐述了电动助力转向系统的结构原理、关键部件及特点,对比分析了3种不同转向系统的性能,并指出未来汽车转向系统的发展趋势。 相似文献
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分析了电动机的转动惯量、转矩传感器刚度、减速机构减速比对汽车操纵稳定性的影响,采用汽车操纵稳定性评价指标确定目标函数,利用遗传算法对电动助力转向系统结构参数进行了优化,并对参数优化前后系统性能进行仿真对比. 相似文献
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助力性能直接关系到汽车转向操作的安全.现以电动助力转向系统的跟踪性能和稳定性为控制系统设计目标,将经典控制理论PID控制理论应用于控制系统设计,创建了电动助力转向系统机电一体化仿真模型.计算机仿真结果证实,所设计的电动转向系统具有良好的跟踪性能和稳定性,仿真结果为电动转向系统的设计提供了依据. 相似文献
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随着汽车工业日新月异的发展,汽车转向系统发生了革命性的变化,由机械转向系统、液压动力转向系统、电控液压动力转向系统发展到电动助力转向系统。因此,应对中职汽修教育中汽车转向系统的教学进行研究与探索。 相似文献
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吴克晋 《中国远程教育(综合版)》1982,(4)
由若干必要的液压元件组合起来,并能完成一定功能的简单液压系统,称为液压基本回路。如由一个定量泵、一个溢流阀、一个节流阀和一个液压缸,以及必要的油箱、滤油器、油管、接头等共同组成一个简单的液压系统,可以通过对节流阀的调节,控制进入液压缸的流量,以达到调节活塞运动速度的目的,即构成通常所谓的“节流调速式速度控制液压基本回路”,简称“节流调速控制回路”或“节流调速回路”。 相似文献
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针对传统液压制动系统应用场景受限的问题,面向智能车设计新型电子液压制动系统,由车辆配备的智能驾驶系统将制动信号传递给制动系统,制动系统由助力制动子系统和备份制动子系统组成,两系统之间通过单向导通梭阀完成解耦。利用系统硬件在环实验,分析电子液压制动系统的动态特性。实验结果表明:影响电子液压制动系统建压响应性与精度的因素众多,为使得系统可以快速响应,应确保整车制动管路排气良好,尽量避免使用制动软管?同时,不宜长时间进行高压力保压工况,避免电机及电机驱动器过热从而降低制动效能。 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献
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Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities. 相似文献
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RUZBEHANI Mohsen 《重庆大学学报(英文版)》2004,3(1):20-25
1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec… 相似文献
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唐芳 《读与写:教育教学刊》2008,5(6)
During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context. 相似文献