“The research team has proposed a second harmonic error self correction method based on characteristic frequency reference to address the problem of angle measurement error in rotation. This method deeply analyzes the mechanism of angle measurement error in rotary transformers, innovatively achieves amplitude adjustment and phase difference adjustment, and effectively corrects the second harmonic error in the rotary transformer output signal. The experimental results show that this method can reduce the amplitude of the angle measurement error of the second harmonic of the rotary transformer by 78.5%, reduce the rate fluctuation of the servo system by 40.5%, and significantly improve the angle measurement accuracy of the rotary transformer and the speed control stability of the servo system. This research achievement not only provides strong support for the optimization and upgrading of servo systems, but also lays a solid foundation for the development of rotary angle measurement technology, which is expected to play an important role in industrial control, aerospace and other fields.”