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农用车辆驾驶座椅悬架系统非线性特性的研究 总被引：4，自引：0，他引：4
本文论证了剪式杆件机构支撑的座椅悬架系统具有垂直等效刚度非线性特性,研究了特性的变化与悬架机构的几何参数、滚轮的滚动阻力系数以及线性弹簧刚度之间的关系。在理论分析的基础上,本文提出了一种新的设计思想——座椅悬架垂直等效刚度可控软特性的设计,并在神牛-25拖拉机上实施了这种设计方案。新驾驶座椅样机的试验表明,这是一种结构简单,隔振效果良好,且适用于各种类型拖拉机和农用车辆的驾驶座椅悬架系统。 相似文献
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为了改善手扶拖拉机驾驶员的乘坐舒适性能,本文给出了一种预紧的X型悬架座椅,并对该悬架进行了理论解析,测定了它的静态特性和手扶拖拉机在凹凸不平道路上行驶时的隔振性能,同时也与手扶拖拉机原海棉弹簧座椅及ISO2631中的振动规范曲线进行了比较。 相似文献
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通过建立在试验基础上的磁流变阻尼器的Binham模型,设计了半主动车辆座椅悬架系统的控制器,并在matlab中对系统进行了仿真分析。结果表明此控制器能有效地抑制座椅的垂向加速度,提高驾驶员的乘坐舒适性。 相似文献
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《拖拉机与农用运输车》2015,(4):15-18
建立了人-椅单自由度系统力学模型,推导了系统振动微分方程和特性参数,分析了不同人-椅质量与人-椅单自由度系统固有频率和等效阻尼系数的关系;基于MATLAB/Simulink,建立了含人-椅单自由度的三自由度车辆-座椅悬架系统仿真模型。结果分析表明,人-椅单自由度系统固有频率随人-椅质量的增加而略微减小,而相对阻尼系数随人-椅质量的增加减小幅度较大。功率谱密度分析表明,人体振动能量主要集中在3 Hz以下的范围内,座椅悬架固有频率分布合理,但人-椅加速度均方根值均大于0.5 m/s2。 相似文献
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车辆悬架控制系统的发展及应用现状研究 总被引：1，自引：0，他引：1
对车辆悬架及其控制系统进行了较为全面的叙述，介绍了车辆悬架的类型与工作原理，着重对以现代控制理论为核心的车辆悬架控制方法予以比较和分析并作出相应的评价，对车辆悬架控制系统的发展方向和应用进行了研究，为深入研究车辆悬架控制系统提供有力的保证。 相似文献
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馈能型车辆主动悬架技术 总被引：3，自引：1，他引：2
在车辆底盘悬架系统中,馈能型车辆主动悬架的发展已受到关注,其功能是在提高车辆行驶平顺性的同时尽可能地回收由不平路面激励引起的悬架系统振动能量,以减少主动悬架的能耗.本文首先对近年来馈能型车辆主动悬架的发展和研究进行了全面回顾,然后着重对电磁式馈能悬架进行了总结,最后对电磁式馈能悬架的核心问题进行了分析.随着电磁技术的日趋成熟,电磁式馈能悬架将会具有良好的发展前景. 相似文献
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《Journal of Agricultural Engineering Research》1998,69(3):249-254
A model to represent the discolouration of dried powder of carrots as a function of temperature was developed. Two types of carrots, Asian and European, containing large amount of lycopene and β-carotene, respectively, were tested. The dried powder was stored under an atmosphere with O2and at three different temperatures, 5,20 and 35°C. The surface colour of the powder was monitored during storage by a Hunter colour ratioa/b. In the proposed model, the rate of oxidation was assumed to be represented by the product of the fraction of concentration of oxidized pigment at arbitrary time and a specific rate of oxidation of pigment. The rate parameters in the proposed model were calculated by fitting the experimental data with smooth curves by trial and error at the end of the induction period but before discolouration took place. The frequency constant and activation energy, expressing the temperature dependence of the rate parameters, were expressed by the Arrhenius relation. The simulation results of a Hunter colour ratioa/bof dried powder at 25°C showed good agreement with the experimental data, suggesting that the proposed model was effective for the prediction of discolouration of dried powder of both types of carrot. The use of the induction period in the manner described may enable the shelf life of dried powder to be predicted. 相似文献
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感官检验棉花的品级,这是农村常见的一种检测手段.它的一个主要特点就是存在不确定性.这是由于检验员的品级检验水平存在一定的差异,其中有很多因素制约着检验的结果.文章对影响感官检验结果的因素进行了系统的分析. 相似文献
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The fractional outflow rate of water from the rumen, measured as the rate of disappearance of the chromium complex of ethylenediamine tetra-acetic acid, was related to a number of dietary factors. A multiple regression equation was derived which expressed fractional outflow rate as a function of the intakes of dry matter, ash, acid-detergent fibre and crude protein.The data analysed consisted of 243 observations for sheep on 59 diets, including forage, concentrate and mixed diets. The ranges covered by the data were: fractional outflow rate 0.7–3.6 day?1; dry matter intake 560–1400g/day; ash 4–30%, acid-detergent fibre 7–41%, crude protein 5–26 % of dry matter; there were no observations for sheep of less than 34 kg liveweight.The equation accounted for 56·3 % of the total variance. Between-sheep variance could not be calculated for the whole of the data but was undoubtedly substantial since, for a sixth of the data, it was known to account for 38 % of the total variance. 相似文献
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从灾害经济学的角度探讨了城镇供水优化调度的必要性和可能性，认为在缺水不可避免的情况下，对供水进行优化调度可以减小缺水带来的损失，产生较好的减灾效益，特别是可以大大减小严重干旱的灾害效应。并根据水资源的特性，提出了缺水损失的计算模式以及优化调度的原则和方法。 相似文献