A novel operational transfer path analysis based on the complex-valued crosstalk elimination method

Operational transfer path analysis (OTPA) can identify significant excitation sources and transfer paths using only operational responses. However, the signal crosstalk between reference points reduces the accuracy of OTPA, and significantly limits practical applications. Existing crosstalk elimination methods always ignore complex-valued information about frequency vibration signals, which causes undesirable analysis results under noncircular complex-valued conditions. In this paper, the transcendental complex maximization of non-Gaussianity theory (TCMN) is introduced for the first time to extend the crosstalk elimination into the complex-valued domain, and the OTPA-TCMN model is constructed to analyze the vibration transmission of the vehicle motor controller unit (MCU) by coupling actual vehicle structures and driving conditions. In the proposed OTPA-TCMN model, the time–frequency calculation module based on the welch method is used to acquire accurate auto and cross power spectrums. To cancel strong crosstalk, the TCMN method is introduced in the crosstalk elimination module to obtain more accurate transmissibility functions, and the contribution calculation module is used to calculate the reconstructed target signal and the contribution of each transfer path. The estimated MCU signal of the proposed OTPA-TCMN and the OTPA based on the complex independent component analysis (OTPA-cICA) and truncated singular value (OTPA-SVD) models are compared to the measured value to validate the proposed model by utilizing actual vehicle experiments. The MCU signal estimated by the proposed model is closer to the measured value, with the errors reduced by more than 20.0% and 5.4% regarding the RMSE and peak values, respectively. Therefore, the proposed OTPA-TCMN model can further improve crosstalk elimination and acquire more accurate analysis results, which can be used as an elegant tool to resolve vibration transfer problems in complex mechanical systems.