基于CNN−LSTM−SAtt的液压支架销轴传感器负载误差预测

Prediction of load error of hydraulic support pin shaft sensor based on CNN-LSTM-SAtt

  • 摘要: 液压支架销轴传感器在剧烈岩层压力下输出信号表现出强非平稳性与时变特征,单一神经网络结构难以同时兼顾多尺度空间特征挖掘与长时序依赖捕捉,且在多尺度特征融合时缺乏自适应权重分配机制,导致误差预测模型的泛化性能受限。针对上述问题,提出了一种融合卷积神经网络(CNN)、长短期记忆网络(LSTM)与自注意力机制(SAtt)的混合神经网络CNN−LSTM−SAtt,并将其用于液压支架销轴传感器负载误差预测。首先,采用变分模态分解(VMD)、快速傅里叶变换(FFT)与希尔伯特变换(HT)组合的方法(VMD−FFT−HT)构建多域特征;然后利用CNN提取频域与时频域的深层空间形态特征,通过LSTM捕获时域信号的长期演变规律;最后引入SAtt根据信号波动特性对多域特征进行动态赋权,进而建立传感器负载响应信号与激励信号的高精度非线性映射。采用力标准机开展的销轴传感器5种典型加载实验结果表明,CNN−LSTM−SAtt模型预测值能够有效修正销轴传感器负载响应信号中的误差分量;相较于传统模型及单一神经网络模型,该模型在预测精度与泛化能力上均表现出显著优势,可实现对复杂工况下液压支架销轴传感器负载误差的有效预测。

     

    Abstract: Under severe strata pressure, the output signals of hydraulic support pin shaft sensors exhibit strong nonstationarity and time-varying characteristics. A single neural network architecture is unable to simultaneously account for multiscale spatial feature extraction and long-term temporal dependency modeling, and it lacks an adaptive weight allocation mechanism during multiscale feature fusion, which limits the generalization performance of error prediction models. To address these issues, a hybrid neural network CNN-LSTM-SAtt that integrated a Convolutional Neural Network (CNN), a Long Short-Term Memory Network (LSTM), and a self-attention mechanism (SAtt) was proposed and was applied to load error prediction of hydraulic support pin shaft sensors. First, a combined method of Variational Mode Decomposition (VMD), Fast Fourier Transform (FFT), and Hilbert Transform (HT) (VMD-FFT-HT) was adopted to construct multidomain features. Then, CNN was used to extract deep spatial morphological features in the frequency domain and time–frequency domain, while LSTM was employed to capture the long-term temporal evolution patterns of time-domain signals. Finally, SAtt was introduced to dynamically assign weights to multidomain features according to signal fluctuation characteristics, thereby establishing a high-precision nonlinear mapping between the sensor load response signal and the excitation signal. The results of five typical loading experiments of pin shaft sensors conducted using a force standard machine indicated that the predicted values of the CNN-LSTM-SAtt model can effectively correct the error components in the load response signals of pin shaft sensors. Compared with traditional models and single neural network models, this model exhibits significant advantages in both prediction accuracy and generalization capability, enabling effective prediction of load errors of hydraulic support pin shaft sensors under complex working conditions.

     

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