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挖掘机液压流量控制方式及节能分析 总被引:1,自引:0,他引:1
阐述挖掘机液压系统流量控制方式的发展过程,及其功率流程和动作过程,分析了节流调速、负流量控制和正流量控制等主要流量控制方式的结构和性能上的优缺点,展望了挖掘机液压系统功率控制方式的发展方向。 相似文献
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KH180—3基础连续墙的抓斗液压系统是真砂80年代的产品,其液压回路存在原理上的重大缺陷。本文针对KH180—3抓斗液压系统作出分析,并提出了解决方案。 相似文献
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在长输管线中,泵站是输油系统中必不可少的部分,而且泵站的运行成本巨大。工况处于经常变化的输油系统是极为普遍的,在这些系统中,通常采用的节流调节法浪费能量。如果能很好地使用变频调速系统,能实现泵站的优化运行。文中介绍了泵机组变频节能工艺理论以及比例定律和相似抛物线的基本原理,并对调速后泵的转速和轴功率进行了计算,进行定速泵与变速泵串联运行试验,并比较了不同操作方式的能耗。 相似文献
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我公司与铁道部武汉工程机械研究所联合研制的JQ600型架桥机是目前国产第一台可架设整孔双线箱梁的架桥机,该机电气系统采用了变频调速,PLC可编程控制,计算机实时监控,远距离遥控等先进技术。Q300T门式起重机采用了蜗轮式调速系统,TE/600轮胎式运梁车采用了液压调平技术等。本文介绍该套设备在秦沈线施工中的应用技术。 相似文献
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通过采用变频调节阀,配合PLC的软件编程,能够使甲醇精馏工艺控制系统的调节阀在一个高水平状态下运行。变频调节阀是采用变频器主回路的电动调节阀,并通过改变节流方式来控制流量,所以它既是一种有效的调节手段,同时又是一个节流节能、降低环境污染的部件,很值得在相关企业推广使用。 相似文献
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基于监测量值变化速度特征的围岩稳定动态综合评判模型 总被引:1,自引:0,他引:1
隧道施工中围岩力学行为受较多因素影响,考虑多因素对围岩稳定的综合评判被越来越多研究者所共识。监控量测是隧道围岩应力、变形状态最直接的反映,其变化速度特征是围岩稳定性评价的重要指标;从围岩稳定性的综合评判模型构建角度来说,所建立的模型必须考虑时间因素进行动态综合评判。据此,文章利用具有速度特征的动态综合评价模型可将评价对象速度状态和趋势融合的特点,提出了基于监测量值变化速度特征的隧道围岩稳定动态综合评判模型的构建方法和评判准则。该模型从多因素角度出发,可以全面地对多时段内被评价对象的变化速度进行测度;所采用的被评价对象变化速度状态和速度趋势计算方法使模型在短时量测或量测数据拟合程度不高时同样适用。该模型的可行性在华蓥山隧道围岩稳定判别中得到了验证,为隧道围岩稳定的综合判定提供了一种新的途径。 相似文献
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通过液压系统的特点,液压油的特性、使用和管理、液压油的污染控制,液压系统中泄漏解决,系统振动噪声防止和系统检测等来说明液压系统保养对减少工程机械液压系统故障率的重要性。以及通过液压系统故障特点及故障处理方法来论证减少工程机械液压系统故障率的有效途径。 相似文献
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工程机械液压系统工作性能的好坏直接决定着工程机械的作业性能。作为液压系统传递动力和信号的工作介质(液压油)的质量,对于工程机械液压系统的使用效果和寿命有着至关重要的影响。应正确使用液压油,防治液压油的污染,最大限度地发挥工程机械液压系统的功能。 相似文献
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根据自流装车管路系统中鹤管流量不同的工艺特点,建立了自流装车管路系统水力计算和装车时间计算的严格模型,讨论了自流装车管路系统水力计算的数值求解方法和基本思路,应用弦截法求解管路系统水力计算方程,求出在一定液位上集油管、鹤管段的流量。采用龙贝格数值积分法求解装车时间,应用VC 6.0高级语言编制了自流装车管路系统计算程序,应用该程序可快速进行工艺设计计算和模拟计算。计算表明:操作的鹤管数越多,各鹤管的流量差别就越大。 相似文献
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Literature has shown potentials of Connected/Cooperative Automated Vehicles (CAVs) in improving highway operations, especially on roadway capacity and flow stability. However, benefits were also shown to be negligible at low market penetration rates. This work develops a novel adaptive driving strategy for CAVs to stabilise heterogeneous vehicle strings by controlling one CAV under vehicle-to-infrastructure (V2I) communications. Assumed is a roadside system with V2I communications, which receives control parameters of the CAV in the string and estimates parameters imperfectly of non-connected automated vehicles. It determines the adaptive control parameters (e.g. desired time gap and feedback gains) of the CAV if a downstream disturbance is identified and sends them to the CAV. The CAV changes its behaviour based on the adaptive parameters commanded by the roadside system to suppress the disturbance.The proposed adaptive driving strategy is based on string stability analysis of heterogeneous vehicle strings. To this end, linearised vehicle dynamics model and control law are used in the controller parametrisation and Laplace transform of the speed and gap error dynamics in time domain to frequency domain enables the determination of sufficient string stability criteria of heterogeneous strings. The analytical string stability conditions give new insights into automated vehicular string stability properties in relation to the system properties of time delays and controller design parameters of feedback gains and desired time gap. It further allows the quantification of a stability margin, which is subsequently used to adapt the feedback control gains and desired time gap of the CAV to suppress the amplification of gap and speed errors through the string.Analytical results are verified via systematic simulation of both homogeneous and heterogeneous strings. Simulation demonstrates the predictive power of the analytical string stability conditions. The performance of the adaptive driving strategy under V2I cooperation is tested in simulation. Results show that even the estimation of control parameters of non-connected automated vehicles are imperfect and there is mismatch between the model used in analytical derivation and that in simulation, the proposed adaptive driving strategy suppresses disturbances in a wide range of situations. 相似文献
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文中对球墨铸铁管在生产中铁水消耗高进行了分析,并提出了改进措施。利用现场分析查找出“管重控制正偏差高”和“拉管成形率低”是造成铸铁管铁水消耗高主要因素。对液压阀台进行改造,采用稳定主机行走、扩大扇形包翻包速度等措施,降低了铸铁管铁水消耗,实现了企业的降本增效。 相似文献
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Jack Haddad Nikolas Geroliminis 《Transportation Research Part B: Methodological》2012,46(9):1159-1176
In this paper, stability analysis of traffic control for two-region urban cities is treated. It is known in control theory that optimality does not imply stability. If the optimal control is applied in a heavily congested system with high demand, traffic conditions might not change or the network might still lead to gridlock. A city partitioned in two regions with a Macroscopic Fundamental Diagram (MFD) for each of the regions is considered. Under the assumption of triangular MFDs, the two-region MFDs system is modeled as a piecewise second-order system. Necessary and sufficient conditions are derived for stable equilibrium accumulations in the undersaturated regimes for both MFDs. Moreover, the traffic perimeter control problem for the two-region MFDs system is formulated. Phase portraits and stability analysis are conducted, and a new algorithm is proposed to derive the boundaries of the stable and unstable regions. Based on these regions, a state-feedback control strategy is derived. Trapezoidal shape of MFDs are also addressed with numerical solutions. 相似文献