共查询到17条相似文献,搜索用时 140 毫秒
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刀具磨损对工件加工精度和表面质量有很大影响,为保证零件加工质量,需对刀具磨损状况进行监测。在实际加工生产中采集工件铣削时的振动信号和力信号,利用短时傅里叶变换,将一维信号转化为二维谱图,建立刀具磨损阶段与频谱图的对应关系,利用Pytorch搭建VGG13卷积神经网络,将频谱图作为卷积神经网络模型输入进行训练,得到刀具磨损监测模型。通过实验对方案可行性及模型准确度进行测试,实验结果表明,利用卷积神经网络进行刀具磨损状态监测的准确度能够达到98%以上,可为实际生产中的刀具磨损状态监测提供参考。 相似文献
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《制造技术与机床》2019,(10)
刀具磨损状况的实时检测是目前机床加工状态监测的难点,而对刀具的振动信号分析的常用方法是利用神经网络模型来判断刀具磨损状态。为解决循环神经网络(RNN)模型训练过程中梯度容易消亡的现象,提出基于长短期记忆神经网络的刀具磨损状态在线监测。刀具在进行切削加工时,首先通过加速度传感器采集刀具振动信号,然后对振动信号小波包变换进行分解是让信号通过不同的滤波器进行有条件的选择,由此形成不同的能量值,用作为长短期记忆神经网络的特征输入,从而诊断出刀具磨损状态的3种状态故障;最后利用长短期记忆神经网络模型对处理时间序列的数据有比较好的效果,它可以捕捉长期的依赖关系和非线性动态变化。此外,通过与多层(BP)神经网络和(BP)神经网络故障诊断方法进行比较,结果表明,LSTM网络对刀具磨损状态在线监测更加有效。 相似文献
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刀具磨损监测过程是一个模式识别过程,模糊推理和人工神经网络都是进行模式识别非常有效的办法,针对模糊系统和神经网络各自表现出来的不足,将模糊推理和神经网络结合起来,充分利用模糊系统在处理结构性知识上的优势和神经网络在自学习和并行处理上的能力,形成模糊神经网络进行刀具磨损在线监测识别.通过研究模糊系统和神经网络的结合形势,... 相似文献
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自动化切削加工过程中,准确可靠地监测刀具磨损状态是保证加工质量和加工效率的关键。针对刀具磨损状态相关特征提取繁琐、准确率低及传统的深度学习网络不能全面提取数据隐含信息等问题,提出了一种以卷积神经网络(CNN)和双向长短时记忆(BiLSTM)网络集成模型为基础并通过在卷积神经网络中添加批量标准化层和采用两个双向长短时记忆网络层的改进模型,该模型通过自动提取小波阈值降噪等预处理和降采样后的切削力、振动和声音信号的空间和时序特征来实现刀具磨损状态监测。将改进模型与CNN-BiLSTM模型及传统的深度学习模型进行对比,发现改进模型在精度和稳定性方面有较大提升。所提方法为准确监测自动化加工过程中刀具磨损状态、提高生产效率和加工质量提供了技术支持。 相似文献
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针对刀具的早期故障监测中因存在强烈的背景噪声而难以提取故障特征的问题,提出了基于二次采样随机共振消噪和B样条神经网络智能识别的故障诊断方法。首先利用在随机共振过程中,噪声增强振动信号的信噪比特性,将刀具振动信号进行随机共振输出,提取有效特征,再输入到B样条神经网络进行智能识别,进而获得刀具的磨损值。同时,为了得到与输入信号最佳匹配的随机共振参数,提出了基于遗传算法的多参数同步优化的自适应随机共振算法,克服了传统随机共振系统只实现单参数优化的缺点。实验结果表明,该方法能实现弱信号检测,能有效地应用于刀具磨损故障诊断中。 相似文献
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Jiwoong Lee Hyun Jung Choi Jungsoo Nam Soo Bong Jo Moonhyun Kim Sang Won Lee 《Journal of Mechanical Science and Technology》2017,31(12):5695-5703
This paper addresses the development of an online tool condition monitoring and diagnosis system for a milling process. To establish a tool condition monitoring and diagnosis system, three modeling algorithms–an Adaptive neuro fuzzy inference system (ANFIS), a Back-propagation neural network (BPNN) and a Response surface methodology (RSM)–are considered. In the course of modeling, the measured milling force signals are processed, and critical features such as Root mean square (RMS) values and node energies are extracted. The RMS values are input variables for the models based on ANFIS and RSM, and the node energies are those for the BPNN-based model. The output variable is the confidence value, which indicates the tool condition states–initial, workable and dull. The tool condition states are defined based on the measured flank wear values of the endmills. During training of the models, numerical confidence values are assigned to each tool condition state: 0 for the initial, 0.5 for the workable and 1 for the dull. An experimental validation was conducted for all three models, and it was found that the RSM-based model is best in terms of lowest root mean square error and highest diagnosis accuracy. Finally, the RSM-based model was used to build an online system to monitor and diagnose the tool condition in the milling process in a real-time manner, and its applicability was successfully demonstrated. 相似文献
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X. Li S. Dong P.K. Venuvinod 《The International Journal of Advanced Manufacturing Technology》2000,16(5):303-307
In automated manufacturing systems such as flexible manufacturing systems (FMSs), one of the most important issues is the
detection of tool wear during the cutting process. This paper presents a hybrid learning method to map the relationship between
the features of cutting vibration and the tool wear condition. The experimental results show that it can be used effectively
to monitor the tool wear in drilling. First, a neural network model with fuzzy logic (FNN), responding to learning algorithms,
is presented. It has many advantageous features, compared to a backpropagation neural network, such as less computation. Secondly,
the experimental results show that the frequency distribution of vibration changes as the tool wears, so the r.m.s. of the
different frequency bands measured indicates the tool wear condition. Finally, FNN is used to describe the relationship between
the characteristics of vibration and the tool wear condition. The experimental results demonstrate the feasibility of using
vibration signals to monitor the drill wear condition. 相似文献
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铣刀健康状况直接影响实际生产加工过程,因此开展铣刀状态监测研究具有较大工程意义。以卷积神经网络为代表的深度学习模型已经逐渐用于监测加工过程中的刀具状态。但是这些模型的可解释性较差,预测结果的差异性也较大。作为一种新颖的卷积神经网络变种,主成分分析模型(Principal component analysis network, PCANet)的可解释性好,但是特征自监督学习能力有待提升,且相关应用案例较少。针对以上问题,拟对PCANet模型进行优化,进而提出了一种激活主成分分析-最大池化-支持向量回归(Activated PCANet with max pooling and support vector regression, APCANet-MP-SVR)模型,用于自适应提取敏感特征并准确预测刀具磨损情况。首先引入tanh激活函数,提高模型泛化能力;再采用最大池化层替代哈希编码和直方图用于特征选择,进一步降低冗余特征规模;最后建立支持向量回归模型实时预测刀具磨损值。应用案例充分证明了所提模型能够更好地用于加工现场刀具磨损值预测。 相似文献