基于Kalman滤波和谱峭度的滚动轴承故障诊断

针对传统共振解调方法难以确定带通滤波器参数的问题,将Kalman滤波技术和快速谱峭度图结合应用于滚动轴承故障诊断中。首先利用齿轮箱原始振动信号建立系统AR模型,通过AIC准则确定模型阶数,通过最小二乘法确定模型参数,对原始信号进行Kalman滤波降噪预处理;并用快速谱峭度图选择最优带通滤波器参数,最后对带通滤波后的信号进行能量算子包络解调,实现故障诊断。工程实测信号的分析结果表明,基于Kalman滤波和快速谱峭度的诊断方法能够很好地诊断轴承故障。     

Butterworth滤波器在丝线张力实时监测系统中的应用

针对实时采集到的丝线张力信号受噪声信号的影响,使产品品质评定、实时张力控制产生误差等问题,提出了运用低通Butterworth数字滤波器对丝线张力信号进行滤波,并给出了Butterworth数字滤波器的设计过程.通过对实际采集到的丝线张力信号进行滤波试验,证明了Butterworth数字滤波器的有效性.     

3utterworth滤波器在丝线张力实时监测系统中的应用

针对实时采集到的丝线张力信号受噪声信号的影响,使产品品质评定、实时张力控制产生误差等问题,提出了运用低通Butterworth数字滤波器对丝线张力信号进行滤波,并给出了Butterworth数字滤波器的设计过程。通过对实际采集到的丝线张力信号进行滤波试验,证明了Butterworth数字滤波器的有效性。     

快速谱峭度与全矢谱结合的滚动轴承故障诊断

针对滚动轴承信号的非平稳调制特性以及单通道分析易造成信息遗漏的缺点,提出了一种基于快速谱峭度算法(Fast Kurtogram)和全矢谱技术的故障特征提取方法。首先利用快速谱峭度算法自适应地确定带通滤波器的最佳中心频率与带宽等参数,根据所选参数构建带通滤波器对双通道故障信号进行滤波,以提高其信噪比;然后对滤波后的信号进行全矢信息融合以保证故障信息的全面性;最后对信息融合后的信号进行包络解调分析以获取振动信号的故障特征信息。实验分析结果表明,该方法能有效地提取滚动轴承的故障特征频率,并提高故障诊断的准确性。     

基于MAX291的无限增益多路反馈带通滤波器

介绍了无限增益多路反馈二阶带通滤波器的电路结构形式,利用开关电容滤波器MAX291内置的运算放大器设计了一个中心频率为50Hz、品质因数为5、增益为1的带通滤波器来实现对检验仪采集信号的滤波处理,给出了滤波器参数计算的具体过程及电路原理,并对滤波前后的效果进行对比。     

基于DDS的数字程控滤波器的设计

数字程控滤波器主要由信号放大电路、滤波电路、时钟脉冲产生电路、单片机控制电路和液晶显示电路等组成。单片机根据输入参数控制仪用放大器的外接电阻和开关电容滤波器的时钟信号,对输入小信号进行相应的放大、低通和高通滤波处理。提出了采用直接数字频率合成技术为开关电容滤波器提供时钟脉冲。有效地控制高／低滤波电路的截止频率。测试结果表明设计的程控滤波器满足设计要求。     

基于Matlab的火灾信号滤波处理及仿真

介绍了一种改进的火灾信号预处理方法--使用带通FIR滤波器进行采样信号的预处理工作,通过滤波器有效去除火灾信号中的干扰信号后,应用Matlab工具对该滤波处理方法进行了仿真分析.     

基于Matlab的火灾信号滤波处理及仿真

介绍了一种改进的火灾信号预处理方法--使用带通FIR滤波器进行采样信号的预处理工作,通过滤波器有效去除火灾信号中的干扰信号后,应用Matlab工具对该滤波处理方法进行了仿真分析.     

滚动轴承振动速度测量中的滤波器设计

借助组合小波,介绍了数字化滤波器设计,用于滚动轴承振动速度信号的低、中、高频段测量。所设计的带通滤波器具有过渡带窄、带通平稳和线性相位特点。并详细地说明了滤波器设计参数和滤波特性,列举了滚动轴承振动速度测量的实例,其有效性在计算机测量中得到证实。     

一种中心频率可自动跟踪的有源滤波电路

在工业自动化测量技术中，为了有效地从众多的信号中提取有用的成份加以分析处理，我们通常采用滤波技术，因为滤波电路能滤除信号频谱中的无用成份。在工业控制中我们接触较多的是中、低频段的信号，而且对信号的分析处理往往是集中在某一特定的频率范围内，所以工程上常用有源带通滤波器处理被测控信号，且尽量使带通滤波器的中心频率与被测信号的频率保持一致，以提高分析处理精度。有源带通滤波器的典型电路见图人其中心频率人为1／2allo，它可通过调节电阻来改变。但在实际测量过程中，经常会碰到有用信号的频率漂移、变化，因此极易导…     

减小表面粗糙度测量高斯滤波幅度偏差

提出了一种减小表面粗糙度测量用的高斯滤波器幅度传输特性偏差的新方法。根据中心极限定理,可以构造出不同的高斯逼近滤波器。用多级一阶巴特沃思滤波器和多级移动平均滤波器分别去逼近高斯滤波器时,两者的幅度偏差方向相反、极值位置相近,所以这两种方法的线性组合可以大大减小偏差。用这两种不同逼近滤波器的并联方法构成的一个简单的线性组合滤波器,去逼近高斯滤波器的幅度传输特性,其幅度传输特性的最大偏差只有0．11％。这种新的逼近方法,算法简单、精度高,实现了表面测量高斯滤波处理的高精度和高效率的高度统一。     

Particle Filter for Estimation and Tracking

In recent years, the particle filter technique has been widely used in tracking, estimation and navigation. In this paper, the authors described several practical filters including the general practical, the extended Kaman practical, and the unscented particle filters. And they explained the degeneracy problem in the practical filter process, and introduced some solved methods. Finally they demonstrated the estimation of different particle filters in non-liner and non-Gaussian situation respectively. The result proved the unscented particle filter had the best performance.     

管式过滤器的新型滤袋骨架

为提高管式过滤器的效率,设计了两种新型的滤袋骨架,一种是方管骨架,另一种是笼形骨架,并与现有圆管滤袋骨架进行了流量对比试验,试验结果表明,这两种新的滤袋骨架可有效提高过滤效率,达到了设计目的。     

基于XJL-150型过滤机的过滤装置改进

橡胶压型之前需要过滤以保证良好的致密性和纯洁性,但滤网需要经常更换。介绍了一种基于XJL-150型过滤机的低成本、可快速更换滤网的过滤装置解决方案,提高了生产效率,降低了成本。     

两种空气过滤器的性能比较及改进措施

本文对两种空压机机前过滤器进行了简要介绍,并分别从过滤效果、使用寿命、吸风口、大气环境和滤料等方面的特性进行了比较分析,最后对自洁式过滤器使用中出现的问题提出了维护办法.     

商标图像平滑滤波算法研究与应用

为了更加准确的完成商标图像的自动检索,在预处理过程中,针对商标图像中存在的噪声,研究了图像平滑滤波算法,分别利用均值滤波、中值滤波和改进的中值滤波方法对商标图像进行了滤波去噪处理.实验结果表明,改进的中值滤波算法在实现去除噪声的同时,既克服了均值滤波处理后图像边缘模糊和图像色变的缺点,也克服了中值滤波法处理后图像形变的不足.     

A universal spline filter for surface metrology

In this study, a novel fractional spline filter is proposed for surface metrology. The filter combines arbitrary order fractional spline function with variational principle, and is endowed with an adjustability of transition characteristic. If the order is high enough, the fractional spline filter can obtain more step-edge-like cut-off characteristic of the low-pass filter, and it can also realize the transmission characteristic of the Gaussian filter with high accuracy if the order equals to two. In addition, if the approximation parameter is set to zero, this filter will be simplified to a form of ordinary spline filter. Therefore, this fractional spline filter is called the universal spline filter. In order to reduce the computation time, the universal spline filter is calculated by a fast Fourier transform (FFT) algorithm. Furthermore, for practical use, an improved method prior to the FFT algorithm is proposed to suppress the end effect. Finally, the efficiency of the whole algorithm in comparison with the ordinary spline filter is demonstrated by the experiments, and it is also shown that the universal spline filter is able to alleviate the end effect significantly.     

The filtering method to calculate the transmission characteristics of the low-pass filters using actual measurement data

The Gaussian filter and spline filter are low-pass filters used in surface roughness estimation methods, and their transmission characteristics are well known. However, the transmission characteristics of the Gaussian filter and spline filter used at actual sites may not be in agreement with their theoretical characteristics. Generally, the spline filter is used with an open profile. Although the transmission characteristics of the periodic spline filter are well known, these transmission characteristics are not those of a nonperiodic spline filter used with an open profile. In the case of a Gaussian filter, the filter width of the theoretical transmission characteristics is ∞. However, a Gaussian filter of filter width λ_c is used at actual sites. This fact is a major problem. To solve this problem, it is necessary that the transmission characteristics of a low-pass filter are obtained from actual measurement data and the filter output. However, it is not possible to calculate the transmission characteristics from actual measurement data owing to the end effect and the discontinuity at each end of the data, etc. In this paper, we propose a new method for exactly calculating the transmission characteristics of a low-pass filter. This method involves the process in which the open profile is considered as a closed profile by repeating it periodically. The transmission characteristics of a nonperiodic spline filter and a Gaussian filter (filter width λ_c) used at actual sites were confirmed by the proposed method. The transmission characteristics of the Gaussian filter of filter width λ_c were almost the same as the theoretical characteristics. However, the transmission characteristics of the nonperiodic spline filter were considerably different from those of a periodic spline filter with well-known characteristics. Moreover, the transmission characteristics of the nonperiodic spline filter were found not to be unique.     

高品质抗混叠滤波器的设计

本文介绍了在采样系统中如何设计高品质抗混叠滤波器。首先介绍了如何用分离元件来设计典型滤波器如贝塞尔滤波器．巴特沃斯滤波器．切比雪夫滤波器等的方法。然后讨论了采用集成电路芯片来设计抗混叠滤波器的方法。     

基于LabView的阀门试验数据采集系统

介绍了利用LabView设计的数据采集系统,重点说明了系统的软硬件组成和虑除干扰的模拟和数字滤波器的设计,为类似的数据采集系统的设计提供参考.