The application relates to the technical field of function test, and discloses a
stress measurement system for spring fatigue state, which comprises an excitation unit, a sensing unit and a
signal processing unit. The excitation unit applies an alternating excitation
magnetic field to the spring to generate a stress-modulated induced
electromotive force signal. The sensing unit collects
magnetic characteristic parameters by using a quadrature differential sensing structure. The
signal processing unit obtains phase components in a tangential signal and a radial reference signal, calculates a dynamic spiral angle deflection based on a
phase difference, determines a dynamic differential compensation coefficient to extract a tangential
principal stress component and compensate for a
magnetic flux leakage vector deviation. Through a space posture modulation and lift gap fluctuation suppression mechanism, the application realizes dynamic alignment of a sensor measurement main shaft and a spring stress
tensor main shaft, effectively eliminates geometric deflection errors caused by large amplitude deformation, and ensures that the
system has high signal-to-
noise ratio and baseline stability under cyclic load.