Tower cranes mixed H 2 / H ∞ under wind load research on active vibration control

Abstract

The offshore platform tower crane is affected by sea breeze, which causes severe vibration, which causes damage to the crane structure and reduces the working efficiency and performance of the crane. Therefore, the vibration suppression under the complex environment of sea breeze has become a key problem to be solved in practical engineering. Firstly, a pulsating wind excitation model with wind speed changing at any time is established to simulate the time sequence of downwind and crosswise wind loads, which is used to reflect the actual wind speed fluctuations. Secondly, the pulsating wind model is applied to the crane finite element model, and the structural vibration characteristics are explored by analyzing the dynamics of the tower crane under wind excitation，the dynamic model of tower crane system under pulsating wind excitation is established, and the system state equation is constructed. Considering the vibration displacement performance of tower crane structure, a hybrid $H_2/H_{\mathrm{\infty }}$ optimal performance vibration active control strategy is proposed. Finally, simulation experiments are carried out. The results show that, compared with the AA controller under the same conditions, the root mean square of displacement under downwind excitation decreases by 65.77%, 64.31% and 63.13%, respectively, and the root mean square of displacement under transverse wind excitation decreases by 62.8%, 65.51% and 62.6%, respectively. The results show that the proposed control method can effectively suppress tower crane vibration.