频谱分析在高速线材精轧机中的应用

阐述了滚动轴承频谱分析的原理,将频谱分析应用于高速线材厂精轧机中,从轴承的特征频率入手,找出轧机异常原因,取得了良好的经济效益。     

形态分量分析在滚动轴承故障诊断中的应用

滚动轴承局部故障振动信号中的周期性冲击是识别故障的关键特征.形态分量分析在由多种形态原子组成的过完备字典基础上提取信号中的不同形态成分,基于这种思想提出了一种基于新型过完备复合字典的形态分量分析方法.依据滚动轴承故障振动信号中分量间的形态差异性,改进字典后该方法可以更具针对性地提取出包含故障特征的冲击分量,配合包络谱分析准确提取故障特征频率,诊断滚动轴承局部故障.对比基于快速谱峭度法的轴承故障诊断方法,该方法可以避免人为选择共振带产生的不准确性和非最优问题,提高了故障诊断效果.通过轴承仿真信号和故障实验信号分析验证了该方法的有效性.     

基追踪在齿轮损伤识别中的应用

针对齿轮的振动特点,设计了复合过完备时频字典,利用基追踪方法在匹配信号特征结构、直接提取特征信息方面的优势分析了齿轮箱的现场测试振动信号.根据基追踪分解结果,在时频联合域内提取了齿轮局部损伤的周期性冲击特征,识别了齿轮点蚀缺陷.与短时Fourier变换和小波变换等时频分析方法进行了对比分析,验证了基追踪检测齿轮损伤的有效性.     

基于移频技术的短时傅里叶变换阶比分析

提出了一种基于移频技术的短时傅里叶变换阶比分析算法.该算法利用傅里叶变换在频域的卷积性质,对原始信号在时域乘以e^-j2πf_it使f_i的频谱能量搬迁到零频处,按一定的频率间隔改变f_i就可以在零频处得到其他频率的频谱能量,以此来提高短时傅里叶变换在时频分析中的频率分辨率.然后在时频面上进行局部阈值降噪,同时跟踪转速的变化,最终应用到变速机械的阶比分析中.与短时傅里叶变换分析结果对比表明,本文方法可以更加准确地跟踪到实际的转速.实际降速过程中轴承信号利用本文方法进行阶比分析,成功提取到轴承的故障特征频率.     

基于小波和小波分形的冷连轧机振动识别方法

针对2180 mm冷连轧机振纹现象的随机性和隐蔽性的特点,基于小波分析和分形理论,系统地研究了能够准确地识别轧机振动的方法.对典型工况下轧机振动信号的分析结果显示,两种方法均能有效地识别轧机振动的现象,为在复杂振动环境下识别振纹振动提供了有效途径,这对于实时监测轧机的运行状况,避免恶性生产事故的发生,进而实现预知轧机振动具有积极的现实意义.     

1580热连轧机组轧机主传动系统建模及振动分析

国内某钢厂1580热连轧机组第二架轧机(简称F2轧机)在轧制特别规格产品时极易发生振动,针对易发生振动的F2轧机主传动系统建立动力学模型,并计算出主传动系统的固有频率和主振型,通过对现场测试的振动信号进行分析,轧辊水平振动信号和主传动接轴的扭振信号具有明显的共性,轧辊水平振动是激励源,导致轧机主传动系统发生扭振共振,进而引起主轧机的强烈振动。消除或减弱轧辊的水平振动是解决轧机振动问题的关键。     

基于NN和MRA的轧机故障诊断信号数据压缩研究

轧机故障诊断信号数据具有有限分辨率、周期性、概率分布冗余和非概率分布冗余等特点。通过构造一新的基于NN的无损数据压缩方案用于压缩轧机故障诊断信号数据的非概率分布冗余空间 ,然后选择一合适的基于MRA的编码系统用于消除轧机故障诊断信号数据的概率分布冗余 ,最后把基于NN的无损数据压缩方案嵌入基于MRA的编码系统 ,获“基于NN和MRA的轧机故障诊断信号数据压缩方法” ,达到较全面消除轧机故障诊断信号数据冗余的目的。实验证明基于NN和MRA的数据压缩方法能有效压缩轧机故障诊断信号数据 ,且恢复的信号数据有较高质量     

应力波技术在棒线材轧机减速机监测诊断中的应用

轧机减速机是钢厂轧钢机械中的关键设备,由于强烈冲击和非平稳载荷等复杂运行工况的影响,采用传统技术手段实现准确的故障诊断难度较大。将应力波技术应用于线材、棒材轧机减速机的监测诊断,过滤设备机体结构产生的低频振动,对设备内部相对运动产生的超声波能量脉冲进行信号采集、处理、分析,从而判断设备健康/不健康状态。在对轧机减速机核心部件常见故障类型及故障结构树进行分析的基础上,通过故障特征匹配识别设备的故障类型及故障严重程度,并以设备开盖检修的情况来验证诊断结论的准确性。     

基于MCKD的轧机齿轮故障源辨识与安全性评估

轧机齿轮箱是轧钢生产线的关键设备,生产线的运行安全很大程度上取决于齿轮传动系统的运行状态。由于轧钢设备的结构复杂,导致系统内部振源数量众多,齿轮振动信号会受到很强的噪声干扰。在齿轮箱的故障诊断研究中,如何滤除观测信号中的噪声和干扰成分,尽最大可能恢复故障源的特征信息,历来都是研究的热点和难点问题。本文引入最大相关峭度反卷积算法(MCKD)算法,以高线轧机齿轮箱为研究对象,力图解决强噪声环境下故障源信息的分离与提取问题。分析结果表明,故障信号经MCKD处理后,故障源的冲击特征得以增强,为齿轮箱的安全性评估提供了重要依据。     

热连轧机耦合振动现象特征研究

某2050热连轧机在轧制高强薄规格带钢时F2和F3轧机出现严重的振动现象。为了摸清轧机振动的特征和现象,研制了一套适合热连轧机耦合振动的在线监测系统,对捕捉的振动信号进行信号时频分析与振动耦合关系分析,通过对同材质同规格、不同材质与规格2种轧钢工况进行分析和轧机振动与成品厚度的关系分析,获得了轧机振动现象及规律,为解决轧机振动提供了大量现场实测数据。     

DASP 系统在高速线材精轧机设备管理中的应用

高速线材精轧机由于转速较高,其机械传动系统易出现突发故障。高速线材精轧机DASP系统能区分齿轮箱中轴承、齿轮、轴系三类零件各自的故障特征信号,采用时域和频谱对故障特征信号进行分析,确定设备的运行情况,为现场设备的安全可靠运行提供了保障。     

Roll Eccentricity Compensation Based on AntiAliasing Wavelet Analysis Method

 Roll eccentricity is an important factor causing thickness variations during hot strip rolling and might define the limit of strip thickness control accuracy. An improved multi resolution wavelet transform algorithm was proposed to compensate for the roll eccentricity. The wavelet transform method had good localization characteristics in both the time and frequency domains for signal analysis; however, the wavelet method had a frequency aliasing problem owing to the less than ideal cut off frequency characteristics of wavelets. This made its component reconstruction of an inaccurate signal. To eliminate inherent frequency aliases in the wavelet transform, fast Fourier transform (FFT) and inverse fast Fourier transform (IFFT) were combined with the Mallat algorithm. This synthesis was described in detail. Then, the roll eccentricity component was extracted from rolling force signal. An automatic gauge control (AGC) system added with a multi resolution wavelet analyzer was designed. Experimental results showed that the anti aliasing method could greatly restrain the inverse effect of eccentricity and the thickness control accuracy was improved from ±40 μm to ±15 μm.     

工艺参数对热轧机振动固有特性影响分析

 某钢厂热连轧生产线F2机架在轧制薄规格产品时发生了强烈的振动现象。为了更好地识别轧机振动的类型,抑制轧机振动,需对轧机系统的固有特性进行全面分析。考虑水平、扭转和垂直系统的振动,并考虑带钢和轧机系统的耦合作用建立热轧机11自由度振动模型,分析轧机系统在无带钢下的固有特性,并分析各阶模态对惯性参数和弹性参数的灵敏度。同时分析带钢和轧机耦合作用下前后张力、入口厚度、出口厚度、摩擦因数、变形抗力等工艺参数对轧机系统固有特性的影响。研究结果表明,带钢和轧机相耦合成一种变结构系统,系统固有特性随着工艺参数的变化而变化,工艺参数主要通过改变第4阶模态和第10阶模态来影响系统固有特性。不同的工艺参数对轧机系统固有特性的影响程度不同,入口厚度影响最为显著,可以通过改变工艺参数来改善系统固有频率。可以为轧机振动类型的识别和振动的抑制提供指导。     

Roll Eccentricity Compensation Based on Anti-Alias-sing Wavelet Analysis Method

Roll eccentricity is an important factor causing thickness variations during hot strip rolling and might define the limit of strip thickness control accuracy. An improved multi-resolution wavelet transform algorithm was proposed to compensate for the roll eccentricity. The wavelet transform method had good localization characteristics in both the time and frequency domains for signal analysis; however, the wavelet method had a frequency-aliasing problem owing to the less than ideal cut-off frequency characteristics of wavelets. This made its component reconstruction of an inaccurate signal. To eliminate inherent frequency aliases in the wavelet transform, fast Fourier transform (FFT) and inverse fast Fourier transform (IFFT) were combined with the Mallat algorithm. This synthesis was described in detail. Then, the roll eccentricity component was extracted from rolling force signal. An automatic gauge control (AGC) system added with a multi-resolution wavelet analyzer was designed. Experimental results showed that the anti-aliasing method could greatly restrain the inverse effect of eccentricity and the thickness control accuracy was im-proved from ±40 μm to ±15 μm.     

小波变换及其在轧辊偏心分析中的应用

阐述了小波分析的数学原理及小波分析在轧辊偏心补偿控制中的应用。从各种随机噪声的轧制力信号这一复杂高频干扰周期波中分离出偏心信号，控制轧机在压下系统实现对偏心的补偿，以提高热轧带钢的厚度精度。还给出了控制系统的构成和仿真结果。     

Spatial Vibration and Its Numerical Analytical Method of Four-high Rolling Mills

The rolls in contemporary four-high mills cannot be maintained parallel during the rolling process. There- fore, four-high rolling mill vibrations take place in six degree of freedom （DOF） leading to spatial behaviors invol- ving vertical, horizontal, axial, torsional, cross and swinging vibration modes resulting in complex relative motions between the rolls. Two numerical methods, modified Riccati-transfer matrix method （Riccati-TMM） and finite ele- ment method （FEM）, are presented to analyze a spatial vibration characteristic of two four-high rolling mills with different stability. The natural frequency and mode shape of four-high rolling mills are obtained, and the clearance has a great effect on natural frequency and mode shape. In addition, field testing experiment is also conducted to measure natural frequency by power spectrum analysis of rolling mill vibration. Experimental results basically agree with those calculated by Riccati-TMM and FEM, which means that the Riccati-TMM and the FEM can be used for analysis of spatial vibration of four-high rolling mill. Meanwhile, the spatial vibration shows more compound vibra- tion behaviors and the negative effect of horizontal, vertical, cross and swinging vibration modes are effectively con- trolled after redesign of rolling mill. These advantages have a great significance for the rolling mill to be operated with a much higher rolling speed and improved yield of products.     

中板轧机参数相关分析和轧制力矩计算

通过对四辊可逆轧机轧制过程测量数据的分析，初步探讨了轧机系统轧制力，牌坊拐角应力、轧制力矩、主电机电流、转速和轧机辊缝诸参数之间的相关特性，分析了用主电机电流和轧制力估计轧制力矩的精度。     

汽车半轴楔横轧机动态特性

为了解汽车半轴楔横轧机动态特性,提高设备整体性能和产品精度,应用ANSYS有限元动力学分析模块,得到了汽车半轴轧机的工作机座和主传动系统的固有频率和振型,并对汽车半轴楔横轧机动态特性进行了详细分析.结果表明,该轧机的工作机座和主传动系统的动态特性设计可靠.     

XGK1400冷轧机的结构分析与优化

采用有限元和三维参数化设计方法,对XGK1400不锈钢冷轧机的机架展开静力分析和模态分析,研究机架的应力和应变分布情况,以及各阶模态振型特点并进行了结构优化。冷轧机的各阶固有频率得以提高,静态特性也得到改善,避免了工频造成的振动误差,有利于提高精密带材的质量。