Technologies On Control Of Time-delay Behavior For Active Heave Compensation

Active heave compensation system(AHCS) is an important equipment of offshore sealift which compensate the relative motion between supplying and supplied ships caused by ocean wind, wave and flow, ensuring the sealift safely and smoothly. However in practice, the big inertia of the crane and the load, and the effects of components characteristics in both hydraulic system and mechanical system cause obvious time-delay that makes poor control quality of the system and affects the stability of the control system. Therefore, it is much significant to research the technologies on control of time-delay in AHCS for improving the control performance and promoting the development of technologies on control for active heave compensation.The details of this paper can be summarized as follows:1. The cause of time-delay in AHCS is analyzed based on the principle of AHCS and the structure of the scaled prototype system. Also the time-delay parameter is identified by using relative principle and experiment.2. A simulation model of AHCS is established by AMESim toolbox, based on which the dynamic characteristic and the time-delay characteristic are analyzed.3. Two control algorithms including fuzzy PID-Smith and GPC are put forward and applied to AHCS, simulated by AMESim/Matlab toolbox, then the control effects of two algorithms are analyzed and compared respectively.4. The results from the experiments on the scaled prototype system show that the control algorithms of time-delay presented in this paper can not only improve the control quality of AHCS but also improve the control performance, which verify the effectiveness of the method researched in this paper.