Abstract:  To improve the quality of marine exploration signals, this paper investigates the stability control problem of a marine vibrator system with uncertain disturbances. Firstly, for the external and internal disturbances caused by the complex working environment in the ocean, an optimal fast finite-time extended state observer (FFTESO) is designed to observe the lumped disturbances of the system. Meanwhile, the observer can estimate the state variables of the system. Secondly, to improve the stability of the vibrator output waveform, a fractional-order finite-time sliding mode surface control scheme is designed to reduce displacement error and output chattering of the controller. Thirdly, the designed control system is proved to be fast finite-time stable via the Lyapunov’s integer and fractional order theorems. Finally, the simulation results verify the effectiveness and feasibility of the proposed control system combining a FFTESO with a fractional order finite time sliding mode control (FOFTSMC). The results show that the maximum relative error of the observer is reduced by 29.5%, and the peak-to-peak chattering value of the controller decreased by 25%.

Key words: marine vibrator system, electro-hydraulic system, fast finite-time extended state observer, fractional-order sliding mode control, finite-time control