Frequency-domain data-enabled predictive vibration control for longitudinal vibration suppression in variable-speed propulsion shafting

A vibration-oriented frequency-domain data-enabled predictive control (FreePC) framework is proposed for longitudinal vibration suppression in variable-speed propulsion shafting. The method constructs the prediction model directly from complex frequency–response data at multiple frequency points within the target band, thereby improving the representation of inter-peak and off-resonant dynamics relative to conventional low-order parametric models. To ensure numerical robustness and real-time feasibility, coherence-guided dictionary construction and explicit realization are introduced. In addition, a cost-function shaping strategy centered on the first longitudinal mode is developed to improve in-band response shaping, and a spectral-forgetting-based online update is incorporated to refresh the control-channel representation after operating-condition changes. Numerical and experimental results show that the proposed method can effectively suppress both tonal and broadband longitudinal vibration and recover effective control performance after stepwise changes among locally steady operating conditions.