Gear fault diagnosis method based on joint weighted envelope noise-resistant correlation of sub-signals

A gear fault diagnosis method based on joint weighted envelope noise-resistant correlation of sub-signals, comprising:

• step 1, collecting, by a vibration acceleration sensor, a signal sequence from a gearbox device of rotating machinery;
• step 2, performing element-wise squaring on the collected signal sequence, to obtain a square sequence of a discrete vibration acceleration signal;
• step 3, performing a low-pass filter on the square sequence of the discrete vibration acceleration signal;
• step 4, computing a square root of the discrete vibration acceleration signal after the low-pass filter to obtain an envelope signal of an original signal;
• step 5, reconstructing the envelope signal according to different time intervals to obtain a series of sub-signals;
• step 6, calculating a fault information representation measure of each of the series of sub-signals based on a L-moment theoretical index;
• step 7, assigning a weight to each of the series of sub-signals based on the fault information representation measure and Sigmoid transformation;
• step 8, calculating a joint weighted envelope noise-resistant correlation function of an envelope signal sequence and the reconstructed series of sub-signals based on the envelope signal from the step 4, the reconstructed sub-signals from the step 5 and the weights of the series of sub-signals from the step 7;
• step 9, drawing a variation diagram of the joint weighted envelope noise-resistant correlation function with a time interval;
• and
• step 10, determining a characteristic frequency based on a reciprocal of a time interval value corresponding to a characteristic peak in the variation diagram drawn in the step 9, and identifying a gear fault to issue an early warning to a staff by a main control unit;
• wherein in the step 1, the collected signal sequence is recorded as s(t), t=1,2,3, . . . , N, where N represents a total number of sampling points, and a sampling frequency is recorded as fs;
• a frequency response parameter of the vibration acceleration sensor is not less than 2 kHz, the sampling frequency f, of the signal sequence is not less than 5.12 kHz and not more than 64 kHz, and the total number of sampling points satisfies max{fs/10, min{fs/8, 2 fs/Fr}}≤N≤fs/2, where Fr represents a lowest rotational speed of all rotating shafts of the gearbox device to be tested.