Application of wavelet scattering and machine learning on structural health diagnosis for quadcopter

The aim of this study was to examine the health diagnosis classification method of quad-copter structures with different mixed faults. The loosening of the motor mount, damage to the propeller, and the loosening of the arm mount were the main fault conditions investigated. Data were first acquired under non‐fault conditions and the conditions of the three types of fault. Then, the features of the vibration and pulse width modulation signals were extracted by root mean square, standard deviation, and sample entropy. Moreover, the features of the audio signal were extracted by wavelet scattering, which contains time‐frequency domain information that provides significant power for classification. In this paper, we propose a simple machine learning method, based on the k‐Nearest Neighbor (kNN), not only for classification but also demonstrating the effi-cacy of the features. To test the limits of accuracy, different configurations of kNN parameters are deployed, in addition to the features. In summary, as a result of the highly efficacious features, de-spite mixed fault conditions, the accuracy reached 90.73%. This method improves the accuracy of mixed faults’ classification and maintains a certain level of classification effectiveness.