对冲压操作在线监测的双频分析

对冲压操作在线监测的双频分析(中文4500字,英文3600字)
自动化和计算机辅助工程的部门、香港中文大学、香港等国家和地区
摘要：由于日益增加的需求，促进产品质量的提高和生产成本的降低，在线监测冲压业务已成为一种普遍的做法，根据一项市场调查，对大多数冲压过程中，监控系统的使用吨位信号和应变信号。最近，一些企图已报告使用加速度信号，因为它们含有丰富的信息资源。不过，据了解，加速度信号容易受到噪音干扰，因而或强或弱。本文介绍了一项研究，利用双谱分析加速度信号。这表明双谱可以抑制高噪声刺激信号杂讯比。它还提取出了特征信号，是与该缺陷的部件（如材料太浓或塞）有关 。实验结果表明该方法是有效的，有良好的潜在应用。我们还提出新的方法为减少在这个过程的计算量。
关键词：监测状态;冲压工艺;高阶统计;双频分析

Bispectral analysis for on-line monitoring of stamping operation
Abstract
Owing to the ever-increased demand for product quality improvement and production cost reduction, on-line monitoring of stamping operations has become a common practice in shop floors around the world today. Based on a market survey, for most stamping processes, monitoring systems use tonnage signals and/or strain signals. Recently, a few attempts have been reported using acceleration signals as they contain rich information and are relatively inexpensive. However, it is known that acceleration signals are vulnerable to the noise disturbances, and hence are less robust. This paper presents a study that uses bispectrum to analyze the acceleration signals. It is shown that the bispectrum can suppress Gaussian color noise to boost the signal-to-noise ratio. It also extracts the features of the signal that are related to the defective parts (such as material too thick or slug). The experimental results demonstrate that the method presented is effective and has a good potential for applications in shop floor. We also present new method for reducing the computation load in the process.
Keywords: Condition monitoring; Stamping process; Higher order statistics; Bispectral analysis