An extended state observer-based sliding mode control method for hydraulic servo system of marine stabilized platforms

Abstract

The marine stabilized platform is a critical apparatus to ensure the stability of offshore equipment and operations with respect to the inertial coordinate system. However, the hydraulic actuating system of the platform is challenging to control due to the severe offshore environment and hydraulic parameter perturbations. Therefore, to improve the stability and anti-disturbance performance of the hydraulic actuators on the marine stabilized platform, an extended state observer-based sliding mode control (ESO-SMC) method is proposed in the paper. We first analyze the kinematic model of the platform and the dynamic model of the hydraulic servo system. Then, ESO-SMC is designed, and its stability is verified. The novel Marine Predator Algorithm (MPA) is used to optimize the parameters in ESO-SMC design. Simulation is performed in MATLAB/Simulink using an engineering ship model and a stabilized platform model on the ship. Compared with the traditional Sliding Mode Control (SMC), Velocity Feedforward PID (VFPID), and PID methods, ESO-SMC performs best in resisting external wave load disturbances and flow gain parameter perturbations. In conclusion, ESO-SMC is a reliable control approach for enhancing the anti-interference performance of the hydraulic servo system on marine stabilized platforms in the simulation.