The invention discloses an aircraft control surface oscillation fault monitoring method based on multi-scale
wavelet transformation, and the method comprises the steps: carrying out the calculation through a PID (
Proportion Integration Differentiation) control law through an
autopilot according to an input flight path command, and obtaining a control surface control instruction deltadepth; a control surface deflection prediction value
delta est is generated based on the
nonlinear model and the control surface control instruction, the control surface deflection prediction value and an actual deflection value
delta mea collected by the sensor module are subtracted to generate a residual
signal Rn, and the residual
signal is decomposed into a plurality of sub-band signals through
wavelet decomposition;
wavelet energy calculation is carried out on the sub-bands possibly containing the control surface oscillation fault signals, whether a fault occurs or not is judged according to the magnitude of an energy comparison threshold value, and the judgment threshold value is determined through Monte Carlo
simulation. According to the method, instruction signals are separated by generating residual errors,
wavelet transform processing is carried out on residual error signals, interference of
noise and irrelevant frequency signals on monitoring performance is reduced, meanwhile, small-amplitude oscillation signals can be effectively monitored according to sub-band wavelet energy serving as a fault criterion, and the monitoring coverage rate of oscillation faults is remarkably increased.