基于异常主导损失的残差跨域网络热障涂层太赫兹测厚方法  

Terahertz based thickness measurement of thermal barrier coatings using the cross-domain residual network with an anomaly-dominant loss

作　　者：曹丙花 孙凤山 范孟豹[2] 叶波 Cao Binghua;Sun Fengshan;Fan Mengbao;Ye Bo(School of Information and Control Engineering,China University of Mining and Technology,Xuzhou 221116,China;School of Mechatronic Engineering,China University of Mining and Technology,Xuzhou 221116,China;Faculty of Information Engineering and Automation,Kunming University of Science and Technology,Kunming 650500,China;Yunnan Key Laboratory of Artificial Intelligence,Kunming University of Science and Technology,Kunming 650500,China)

机构地区：[1]中国矿业大学信息与控制工程学院,徐州221116 [2]中国矿业大学机电工程学院,徐州221116 [3]昆明理工大学信息工程与自动化学院,昆明650500 [4]昆明理工大学云南省人工智能重点实验室,昆明650500

出　　处：《仪器仪表学报》2024年第11期287-299,共13页Chinese Journal of Scientific Instrument

基　　金：国家自然科学基金(62071471)项目资助。

摘　　要：热障涂层微观结构、粗糙度不均匀和厚度小幅变化对太赫兹波影响高度混叠,降低了测厚精度。为此,提出了异常主导损失函数驱动的残差跨域网络测厚方法,减少检测离群值。首先,构建了太赫兹信号解析模型,探究出飞行时间与折射率分别可由时域与频域数据求解,设计了快速傅里叶变化层映射出频域特征,基于门控循环网络层感知时域信号变化,依据测厚机理,提出以除法层连接,形成了残差跨域网络结构。然后,由于粗糙度与微观结构变化对太赫兹信号峰值影响混叠,创新构建了异常主导损失函数,增大离群值权重,使网络聚焦于修正测厚离群值。最后,制备了热障涂层样品,开展了太赫兹实验,结果表明,所提出方法最大测厚相对误差小于2.5%。The influence of non-uniform microstructure,uneven roughness and small thickness change of thermal barrier coating on terahertz waves is highly overlapping and reduce the accuracy of thickness measurement.To address this,a thickness measurement method based on a residual cross-domain network driven by an abnormal dominant loss function is proposed to minimize prediction outliers.First,an analytical model of terahertz signals is developed,demonstrating that two key parameters for thickness measurement—time of flight and refractive index—can be derived from time-domain and frequency-domain data.A Fast Fourier Transform layer is introduced to extract frequency-domain features,while a gated recurrent layer captures changes in the time-domain.Additionally,a division layer is designed based on transmission rules,enabling the construction of an interpretable cross-domain residual network.Given the overlapping effects of roughness and microstructural changes on terahertz signal peaks,an abnormal dominant loss function is established to assign greater weight to outliers.Finally,thermal barrier coating samples were prepared,and terahertz experiments were conducted.The results demonstrate that the proposed method achieves a maximum relative thickness measurement error of less than 2.5%.The influence of non-uniform microstructure,uneven roughness and small thickness change of thermal barrier coating on terahertz waves is highly overlapping and reduce the accuracy of thickness measurement.Therefore,the thickness measurement method of residual cross-domain network driven by abnormal dominant loss function is proposed to reduce the predicted outliers.Firstly,an analytical model of terahertz signals is built to illustrate that two key factors of terahertz thickness measurement,time of flight and the refractive index,can be solved by the time-domain and frequency-domain data.The fast Fourier transform layer is originally proposed to obtain the feature of frequency domain,and the gated recurrent layer is constructed to sense t

关 键 词：太赫兹无损检测 热障涂层 厚度测量 异常主导损失 残差网络 

分 类 号：TH744[机械工程—光学工程]