非平稳随机载荷下海洋平台振动半主动控制

提出了一种新的变刚度半主动控制方法，采用短时波面特征信息和开环控制策略，由波面特征信息通控制器实时改变TMD的刚度，以达到对系统最优状态的跟踪，克服信号处理系统和作动器的延时可能带来的系统稳定性问题。将一次风暴潮强非平稳过程描述成许多短时的平稳过程，分别以平台上甲板位移、加速度响应最小作为控制作动器优化目标，优化得到控制装置刚度变化的时域过程，实现TMD变刚度对海洋平台甲板加速度及位移的振动控制。在平台顶部甲板安装半主动控制装置后，平台甲板的加速度标准偏差平均降低21％。这种半主动控制装置既有主动控制效果好、适用范围广的性质，又有被动控制装置造价较低、可靠性高的特点。

Semi-active Vibration Control for an Oil Platform under Nonstationary Wave Force

A new device is designed and the control algorithm is presented for the CII oil platform to mitigate wave_excited structural vibration.To study its behavior as subjected to wave loading,the actual CII oil platform located in Bohai Bay of North China is modeled as a two degrees_of_freedom dynamic system.With the strategy of open_loop control algorithm,a long_term strong nonstationary wind_excited wave process can be described as a series of short_term stationary wave processes which are transferred to the controller of the device to get the systemic optimal trace to suppress the structural vibration.With a new and innovative semi_active variable stiffness tuned mass damper installed on the top deck of the platform,the coupled equations are deduced,and both the structural vibration behavior and the performance of the control device are studied under strong wind_exited states of the sea.The analysis shows that the mean value of the deck acceleration standard deviation can be decreased by 21% compared with that of without the device.The result also indicaties that there are many advantages of this device which not only provides a reliable and inexpensive means but also hsa a good performance of achieving vibration control for the offshore engineering structure.