RESUMEN
To address the challenge of low fault diagnosis accuracy due to insufficient bearing fault data collected by single-sensor, a rolling bearing fault diagnosis method based on multi-sensor bi-layer information fusion under small samples is proposed. In the first-layer feature fusion, first, aiming at the problem that the number of intrinsic mode functions (IMFs) and the penalty factor in the variational mode decomposition (VMD) is challenging to determine, the Aquila optimizer algorithm is introduced to search for the optimal solution independently. Decomposition of bearing vibration signals acquired by multiple sensors using a parameter optimized the VMD method to obtain IMFs. The 12 time-domain features are then extracted for each IMF, and the maximum information coefficient (MIC) between each IMF time-domain feature and raw signal time-domain features is calculated. Finally, the feature fusion composition ratio is calculated according to the MIC mean of each. In the second layer of data fusion, the fusion composition ratio calculated in the first layer is used as a weight-to-weight and reconstructs the signals of each sensor to constitute a fused signal. Then, the fused signals are input into the fault diagnostic model, and fault pattern recognition and fault severity recognition are performed at the same time. The results show that the accuracy of the method proposed in this paper is higher than that of the comparison method on both the public dataset and the self-built experimental bench dataset, and it is an accurate, stable, and efficient fault diagnosis method.
RESUMEN
We examine the effect of cavity field fluctuations on Kerr nonlinearity in an atom-assisted optomechanical system. It is found that a new self-Kerr (SK) nonlinearity term, which can greatly surpass that of a classical Λ type atomic system when the hybrid system has numerous atoms, is generated based on cavity field fluctuations by atom-cavity interactions. A strong photon-phonon cross-Kerr (CK) nonlinearity is also produced based on cavity field fluctuations. These nonlinearity features can be modified by atom-cavity and optomechanical interactions. This work may provide a new method to enhance the SK nonlinearity and generate the photon-phonon CK nonlinearity.
RESUMEN
We consider the coupling effect between interdot tunneling coupling and external optical control field to study the linear optical property and the formation of temporal optical solitons in a quantum dot molecules system, analytically. The results show that the double tunneling induced transparency (TIT) windows are appeared in the absorption curve of probe field because of the formation of dynamic Stark splitting and quantum destructive interference effect from the two upper levels. Interestingly, the width of the TIT window becomes wider with the increasing intensity of the optical control field. We also find that the Kerr nonlinear effect of the probe field can be modulated effectively through coherent control both the control field and the interdot tunneling coupling in this system. Meanwhile, we demonstrate that the formation of dark or bright solitons can be practical regulated by varying the intensity of the optical control field.
