共查询到20条相似文献，搜索用时 95 毫秒
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振动筛轴承的额定寿命是在理想状态下，根据轴承类型、径向当量动负荷、回转次数、轴承额定动负荷等参数进行计算的。在实际使用中，影响振动筛轴承寿命的因素很多，如果使用不当，其寿命将受到很大影响。振动筛用轴承常见的有球面滚子轴承和短圆柱滚子轴承(在SKF轴承中有NU型和NJ型两种)两大系列轴承。 相似文献
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采用孔式节流和多孔材料节流,提出了复合节流式静压气体轴承,充分发挥两种节流方式各自的优点,使轴承具有更好的静态性能。利用Fluent计算轴承内流场参数并分析流场特性,将复合节流式静压气体轴承的稳定性、承载能力和刚度与传统节流形式轴承作对比,并通过实验验证计算结果。结果表明:在相同的几何参数下,复合节流式轴承稳定性优于单一孔式节流;在一定气膜厚度范围内,复合节流式静压气体轴承承载能力和刚度明显高于多孔材料节流和孔式节流;实验结果与计算仿真结果基本一致。 相似文献
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本文针对初轧大电机转子轴静压轴承进行理论分析,并与现场实测数据进行比较表明,理论分析结果与实际使用系统相符合,为初轧大电机静压轴承的润滑问题提供了理论依据。 相似文献
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《技术与创新管理》1996,(3)
多功能巷道支架试验台 项目简介 多功能巷道支架试验台主要用于矿山巷道支架力学性能试验的大型试验设备。试验台由5个大型封闭式钢结构框架组成,它借助于60个加载油缸和38个调位油缸,使整个试验的加载试验过程和试验台大型结构件的位移实现了液压控制,并可根据不同试验方案的加载点位置要求在长、宽、高3个方向自由调节。试验台的特点是可在多个支架联合工作状态下研究支架结构的稳定性,架间连接件的作用及各支架的受载状况和相互影响。试验台设计构思新颖,使用方便,功能超过了国内外同类设备。经专家评议,该试验台达到了国际领先水平。 多功能巷道支架试验台是我国目前唯一研究矿山支护结构力学性能的大型试验设备,为我国矿山巷道支护研究和支护设备生产提供了现代化的实验检测手段,对促进我国巷道支护向规范化、标准化和科学化发展具有重要意义。 服务方式 该试验台可为新研制的巷道支架及其构件进行力学性能试验和对成批生产的巷道支架进行质量检测,也可对矿井其它支护物(如各种垛子、墩柱和巷旁充填物等)以及隧道、桥梁建筑和地下工程中某些大型结构件进行力学性能试验。 相似文献
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介绍了当前变风量空调系统的常用控制方式,阐述了静压重设控制方式的具体流程,分析了静压重设控制方式的特点及应用意义。 相似文献
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针对电力系统对短期电力负荷预测精确性的需求，以长短期记忆算法为基础，采用差分自适应进化算法对其进一步改进，从而提出一种基于机器学习的混合算法（SaDE-LSTM）对电力负荷进行短期预测。基于我国2004—2018年间月度社会用电负荷数据，对改进后的混合算法进行性能测试，首先利用差分进化算法的自适应变异和交叉因子来优化长短期记忆算法的初始参数，在此基础上，运用寻优得到的参数训练长短期记忆算法从而得到优化后的预测结果。为证明其优越性，对同组数据采用支持向量机（SVM）、反向传播神经网络、自回归积分滑动平均等算法分别预测。各方法预测结果和真实结果对比分析证明，SaDE-LSTM算法对时间序列数据量要求较低，同时相比其他传统算法有更高的预测精度。该改进算法能够为参与电力系统调度的虚拟电厂、负荷聚合商等对小样本和高精度预测有需求的主体提供参考。 相似文献
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对于高负荷条件下的WEB服务器集群的负载均衡,主要问题之一是如何获取实时负载及负载能否有效衡量整个网络的利用率和性能,即须找出合适的参数作为负载并动态获取到。本文就这一问题提出了对交换设备使用SNMP动态采集负载信息,用于负载模型中。主要思路是利用NET-SNMPAPI对管理设备发送get-request请求包,再处理响应包中的变量值为所需格式,接着运用到综合负载模型中,最后采用最小加权轮询调度处理用户请求。 相似文献
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A general theoretical foundation of structural system reliability analysis is presented. Both an analytical and a numerical formulation for evaluating a relative reliability measure of a structural system is developed in which general random factors affecting both strength and loading can be included. The reliability of a suspension bridge is analyzed as an example; the effect of dead load, used as a proof load, is also studied. 相似文献
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博罗水文站属国家一类精度水文站,是东江干流的控制站。近年来由于东江下游河道大规模的采砂活动,导致河床不断下切,潮水上溯,现测验河段已成感潮河段。同时又受惠州东江水利枢纽蓄放水发电影响,这两个原因致使博罗站的流量测验及资料整编造成严重影响,使得传统的流量测验及整编方法解决不了博罗站的主要问题。为此博罗站引进了在线测流系统,进行流量连续实时监测。文章结合水文资料整编软件HDPS就博罗站采用在线测流系统的流量资料整编方法进行探讨。 相似文献
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在定量装液自动控制系统中为了提高计量精度,论文提出了应用单片机实现对油品温度补偿的控制方案,基本上能够解决上述问题。 相似文献
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Yogendra Arya 《Journal of The Franklin Institute》2018,355(5):2662-2688
The interconnected large-scale power systems are liable to performance degradation under the presence of sudden small load demands, parameter ambiguity and structural changes. Due to this, to supply reliable electric power with good quality, robust and intelligent control strategies are extremely requisite in automatic generation control (AGC) of power systems. Hence, this paper presents an output scaling factor (SF) based fuzzy classical controller to enrich AGC conduct of two-area electrical power systems. An implementation of imperialist competitive algorithm (ICA) is made to optimize the output SF of fuzzy proportional integral (FPI) controller employing integral of squared error criterion. Initially the study is conducted on a well accepted two-area non-reheat thermal system with and without considering the appropriate generation rate constraint (GRC). The advantage of the proposed controller is illustrated by comparing the results with fuzzy controller and bacterial foraging optimization algorithm (BFOA)/genetic algorithm (GA)/particle swarm optimization (PSO)/hybrid BFOA-PSO algorithm/firefly algorithm (FA)/hybrid FA-pattern search (hFA-PS) optimized PI/PID controller prevalent in the literature. The proposed approach is further extended to a newly emerged two-area reheat thermal-PV system. The superiority of the method is depicted by contrasting the results of GA/FA tuned PI controller. The proposed control approach is also implemented on a multi-unit multi-source hydrothermal power system and its advantage is established by Correlating its results with GA/hFA-PS tuned PI, hFA-PS/grey wolf optimization (GWO) tuned PID and BFOA tuned FPI controllers. Finally, a sensitivity analysis is performed to demonstrate the robustness of the proposed method to broad changes in the system parameters and size and/or location of step load perturbation. 相似文献
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负荷模型对电力系统仿真结果有重要影响,由于负荷特性的辨识是负荷建模的主要方面之一,故提高负荷模型的准确度就需要对负荷特性分类进行研究。文章在详细分析SOM自组织映射神经网络结构的基础上,采用了基于SOM神经网络的负荷分类方法,以负荷模型参数作为负荷动态特性分类特征向量,应用SOM神经网络对负荷特性进行分类,并对分类结果进行测试,结果表明该方法可有效地对负荷样本进行分类。 相似文献
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Active Noise Control (ANC) systems are increasingly used to reduce environmental noises. A hybrid ANC system is a combination of feedforward and feedback structures in which the anti-noise signal is generated using both structures. Employing the advantages of feedforward and feedback structures enables a hybrid structure to have a high performance in controlling unwanted noise. The step size of filters used in ANC systems plays an essential role in its performance. Any variation from the appropriate value leads to divergence or inefficiency of the noise controller system. These parameters are often set experimentally, which is a time-consuming task. In addition, there is no guarantee that the system can adapt itself to situational changes. The objective of this paper is to propose a new self-tuning hybrid ANC method. Using this technique, the system continuously estimates the parameters during its operation. Results of computer simulations demonstrate the robustness of the proposed method. 相似文献
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This study deals with the stability analysis of a flexible structure with one and only one boundary control. The system is composed of three parts: a cart (motorized platform), a flexible cable, and a load mass attached to the lower part of the cable. This situation leads to a hybrid system as a mathematical model for the cable dynamics: one partial differential equation coupled to two ordinary differential equations. Despite the presence of a time-delay in the top-end of the cable, we are able to prove that the hybrid system is well-posed in the sense of semigroups theory and more importantly, only one boundary control can guarantee the exponentially decay of the energy of the system under reasonable conditions on the parameters of the system. This outcome considerably improves the result recently established in [17], where two more controls are required: one interior (Kelvin–Voigt) damping which acts over the entire cable and another boundary control which is exerted on the lower-end of the cable. Furthermore, we provide an estimate of the exponential decay of the system by means an appropriate Lyapunov functional. Lastly, numerical examples are presented in order to ascertain and highlight our theoretical outcomes. 相似文献