Helicopter fuselage vibration is mainly caused by rotor excitation loads. Active vibration control (AVC) has become an effective means to reduce helicopter fuselage vibration. The higher harmonic control (HHC) algorithm in the frequency domain has been widely used in AVC due to advantages such as simplicity, strong robustness, and ease of implementation. However, HHC has drawbacks such as long updating intervals of control inputs and updating delays. The harmonic synchronous identification-updat