Modeling of active heave compensation system of deep-sea mining based on dynamic vibration absorber and its H∞ robust control

The heave compensation system is vital for the deep-sea mining system undergoes excessive vibrations due to irregular wave loads for both normal operating and extreme conditions. To ensure its safety and operation efficiency, a novel active heave compensation system of deep-sea mining based on dynamic vibration absorber was proposed in this paper. The three-degree-of-freedom dynamic models of active heave compensation system based on dynamic vibration absorber in irregular wave are established. A H_∞ Robust controller is designed for active heave compensation system by applying robust loop shaping control. The performance of H_∞ robust controller and its robustness stability of the system are simulated and analyzed in frequency domain. The results show that the performance of the system in wave energy concentrated frequency domain of China´s deep-sea mining field was improved by the concentrated weighting of acceleration output. And it also shows that the designed H_∞ controller is perfect in system robustness stability against some parameter fluctuations of the system model. Therefore the designed active heave compensation system is practical to isolate the lift pipe and its support platform from the significant vibration of the ship motion induced by the irregular wave.