共查询到20条相似文献,搜索用时 125 毫秒
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《振动工程学报》2017,(2)
面向工程的需要研制了主被动复合、传感作动一体化的智能减振器。它基于传统的被动隔振结构,集成了主动执行机构、功率放大设备及高低通滤波器、加速度误差传感器及后续的放大和滤波电路,与脱机运行的主动控制器构成针对舰船机械设备的主动减振系统。基于该系统建立了柴油发电机组主动减振演示台架。整个台架通过4个智能减振器坐落在一块模拟船体结构的弹性钢板上,通过测量弹性钢板的振动情况来评价主动减振系统的减振性能。演示台架试验结果表明,智能减振器在800Hz以内的总振级有33dB以上的被动减振效果,在此基础上的主动控制对200Hz以内的多根线谱均有很好的控制效果,线谱最大有30.8dB的主动衰减量,200 Hz以内总振级的主动衰减量达到20dB。综合主被动减振的效果,智能减振器可以将演示台架的柴油发电机组0~800 Hz范围内的振动总振级衰减47.2dB以上。 相似文献
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船舶管系减振材料的应用研究 总被引:1,自引:1,他引:0
为适应我国舰船减振降噪的需要,试制出QGD-1和QGD-2两种穿孔型隔振垫,主要用于管路马脚,也可用于基座等振动部位。对两种隔振垫的阻尼性能、阻燃性能、耐油性能与国外同类产品进行了比较。经管路模型试验和水泵机组试验证明,这两种隔振垫可使管路系统振动加速度级明显下降。 相似文献
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直升机结构响应主动控制飞行试验 总被引:1,自引:0,他引:1
为验证结构响应主动控制方法在直升机振动控制中的有效性,以某轻型直升机为验证机,基于具有在线识别功能的时域自适应控制算法,进行了直升机结构响应主动控制飞行试验研究。给出了飞行试验方法、试验系统组成、试验内容及其过程。通过对飞行试验数据的处理分析,对减振效果进行了评估。试飞结果表明:ACSR(Active Control of Structure Response)系统对各测点的垂向振动均有减振效果,各速度状态下的全机垂向减振效率在30%~66%之间,巡航速度状态下具有最佳的减振效率;此外,各测点的侧向振动水平也有一定程度的减小。 相似文献
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MTU柴油发电机组隔振装置振动固有特性分析 总被引:13,自引:2,他引:11
MTU柴油发电机组隔振装置振动固有特性分析沈荣瀛,卢峥(上海交通大学振动冲击噪声研究所)一、前言为了减少和降低舰船的辐射噪声,最常用的方法是对舰船内主要振动源,如主推进动力装置、柴油发电机组、水泵、风机等等采用弹性安装的方法进行振动隔离,降低各个振动... 相似文献
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对于一种新型组合式道床试验系统的结构,进行了静动态试验,研究组合式道床系统在承受大载荷作用下,钢轨以及道床板结构受力变化规律,并将静态试验数据与理论计算结果相互对比。在负载状态下对该系统进行了动态锤击试验,验证安装谐振浮轨减振扣件及道床隔振垫组合道床系统的总体减振效果。静态力学特性数据表明:谐振浮轨扣件及道床隔振垫组合式系统理论计算与实际实验值基本一致;动态试验结果得到该组合道床系统在实验室等效轴载14 t~16 t条件下20 Hz~200 Hz频率范围,平均减振量可达到25 dB。 相似文献
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针对舰船隔振系统的主要动力学设计参数,以水下辐射噪声为考察目标,设计不同系统动力学参数组合下的结构模型水下试验,考察参数变化对结构与水下辐射噪声的影响。试验结果显示有工程价值的规律,对隔振装置的结构动力学设计具有应用价值。 相似文献
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针对多模态振动信号的在线监测和跟踪,提出基于随机子空间(SSI)和粒子滤波(PF)算法的仿真振动信号在线监测和跟踪方法。通过SSI算法提取得到振动系统的模态主频和阻尼比,根据振动系统模型模态主频和阻尼比的计算公式,得到系统的状态矩阵和输出矩阵。将计算所得状态矩阵和输出矩阵代入状态方程,利用PF算法进行信号的在线监测和跟踪,实现信号的降噪处理和预测分析。对于大型机械、桥梁等建筑物,对其进行在线监测保障其正常营运对社会经济发展具有深远影响。文中利用SSI算法提取系统的模态参数,进一步构建振动系统的状态矩阵和输出矩阵,并利用PF算法进行信号滤波抑噪和预测,在此基础上可以对结构状态实施在线监测及预警控制,实际大桥斜拉索振动信号测试也表明本文算法可以提供稳定可靠的信号跟踪与预测技术。 相似文献
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An adaptive, optical, radial basis function classifier for handwritten digit recognition is experimentally demonstrated. We describe a spatially multiplexed system that incorporates an on-line adaptation of weights and basis function widths to provide robustness to optical system imperfections and system noise. The optical system computes the Euclidean distances between a 100-dimensional input vector and 198 stored reference patterns in parallel by using dual vector-matrix multipliers and a contrastreversing spatial light modulator. Software is used to emulate an electronic chip that performs the on-line learning of the weights and basis function widths. An experimental recognition rate of 92.7% correct out of 300 testing samples is achieved with the adaptive training, versus 31.0% correct for nonadaptive training. We compare the experimental results with a detailed computer model of the system in order to analyze the influence of various noise sources on the system performance. 相似文献
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《Science, Measurement & Technology, IET》2009,3(5):354-363
For many years incipient partial discharge (PD) faults in power cables have been identified through off-line investigation techniques. More recently, in an effort to allow pro-active asset management of the medium-voltage (MV) cable network to be carried out, continuous on-line monitoring systems are being installed with the aim of reducing unexpected failures. This study presents work on the analysis and handling of acquired data, from the point of view of asset management and the PD activities observed in an on-line cable monitoring systems. Initially, a review of on-line against off-line cable PD monitoring is presented, in terms of their setups and their respective advantages and disadvantages. The study then presents the authorspsila experience of applying wavelet-based denoising techniques [both the discrete wavelet transform (DWT) and the second generation wavelet transform (SGWT)] to PD data denoising. Results of a study on the on-line PD-based monitoring of MV underground cables that are presented in the following section demonstrate that PD activity which is observed in on-line monitoring also has an associated high level of electrical noise that must be removed to allow proper identification of the PD signals and the denoised PD activity is seen to vary with time. Finally, the necessity of developing a means by which knowledge rules can automatically be acquired from on-line condition monitoring data, to reduce reliance on human expertise, is discussed. 相似文献
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Single-beam spectra were collected over the combination region of the near-infrared spectrum for 80 samples collected from 15 people over a two-week period. Partial least-squares (PLS) regression was used to generate an optimized calibration model for urea. PLS calibration models accurately measure urea in the spent dialysate matrix. Prediction errors are on the order of 0.15 mM, which is sufficient for the clinical assessment of the dialysis process. In addition, the feasibility of a global calibration model is demonstrated by generating a calibration model from samples and spectra obtained from 12 people to predict the level of urea in samples collected from 3 different people. In this case, the standard error of prediction is 0.09 mM. Spectra were modified in order to systematically examine the impact of resolution and noise. Little impact is observed by altering the spectral resolution from 4 to 32 cm-1. Spectral noise, however, plays an important role in the accuracy of these calibration models. Increasing the magnitude of the spectral noise increases the prediction errors and increases the width of the spectral range necessary for extracting the analytical information. The utility of the method is demonstrated by analyzing dialysate samples collected during actual dialysis treatments. In addition, the necessary resolution and spectral quality necessary for reliable on-line urea monitoring is identified. These findings indicate that a dedicated, on-line urea spectrometer must posses a resolution of 16 cm-1 coupled with a sample thickness of 1.5 mm and spectral noise levels on the order of 25 micro-absorbance units when measured as the root-mean-square (RMS) noise of 100% lines. 相似文献
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阐述了飞机结构健康监测的概念和基本组成部分,从监测结构和监测量方面梳理了常见的监测对象;评述了近期结构健康监测数据处理的典型研究成果,主要包括数据采集和预处理、数据分析两个方面,可以看到智能计算的思想和方法越来越多地应用在其中;展望了飞机结构健康监测未来走向大范围在线工程应用的趋势,有针对性地提出了三个要点,分别是机载化在线监控系统硬件的研发、算法的开发和行业的标准化,然后梳理了飞机结构健康监测传感器技术的近期研究案例,并介绍了新兴算法应用于在线监测系统中的案例,为进一步推动飞机结构健康监测系统研究提供参考与借鉴。 相似文献