Disturbance compensation control method for improving waveform accuracy of controlled active seismic source

Abstract Controlled active seismic sources (CASS) have advantages of environmental friendliness, low-cost deployment, high waveform repeatability and precise control, and have been successfully applied in geophysical exploration and seismic time-lapse monitoring. Since the large rotational inertia of the eccentric rotation structure in CASS, combined with undetermined disturbances, waveform distortion often occurs during operation, thereby reducing the accuracy of the output seismic waveforms. To address this issue and improve waveform accuracy, a control method based on disturbance observation and feedforward compensation is proposed. First, dynamic model of the CASS system is derived, and a gravity disturbance equation is established to estimate gravity-induced perturbations. Next, to account for undetermined disturbances and modeling errors, a disturbance observer is introduced. Subsequently, a seismic source controller is designed, incorporating feedforward compensation for disturbances along with closed-loop feedback to enhance the control accuracy of the seismic waveform. Finally, simulations and physical experiments are conducted to assess the system’s performance. The experiments, which involve the excitation of linear frequency-modulated signals using the CASS and signal extraction via the Wigner–Hough transform, demonstrate the effectiveness of the proposed method.