Study on a fuzzy MR damper vibration control strategy for offshore platforms

In order to reduce the dynamic responses of offshore platform effectively, fuzzy magnetorheological controller is adopted to control the offshore platform in this paper. Taking the error of offshore platform displacement responses and error variety as inputs, and the optimal control force as output, the optimal fuzzy controller is designed. Considering the limits for output force, semi-active control strategy is used to revise the output control force, which approximates to the optimal active control force calculated by the fuzzy control strategy. Finally a numerical example of offshore platform is used in this paper. The simulation results show that vibration of offshore platforms by using fuzzy control method is reduced effectively. In addition, the influence of uncertainties of external loads parameters and structural damping on control effect is analyzed in detail. The results indicate that the proposed method has good fuzziness on uncertainties of structural damping, while it has some weaker fuzziness on uncertainties of external loads parameters than on uncertainties of structural damping.