基于内流动力学的海洋输油柔性立管鲁棒边界控制

Robust boundary control for flexible fluid-transporting marine riser based on internal fluid dynamics

海洋输油柔性立管的振动是引起立管疲劳破坏的主要原因,对其研究边界控制是消除振动疲劳、减少断裂的有效方法.本文引入内流动力学,完善了立管原始无穷维分布参数模型,更好地表达了柔性立管的动力学响应.为抑制柔性立管在内外流激励下的振动奠下基础,本文用Lyapunov直接法对柔性立管系统的稳定性和状态一致有界性进行了证明,设计了边界控制器调节柔性立管的振动,其中控制器使用了符号函数来消除不确定性环境扰动对振动控制效果的影响,提高了系统的鲁棒性.仿真实验表明本文所设计的控制算法有效地减少了柔性立管的振动偏移量.

The vibrations caused by random ocean currents will make fatigue fractures for the flexible marine risers. Boundary control can lower the risk of fatigue fracture by reducing vibration displacements of file riser. By introducing internal fluid dynamics to the original infinite dimensional parameter distribution equation （PDEs）, ＇we develop an improved model for describing the dynamic behavior of risers, laying groundwork to suppress the marine riser vibration excited by internal and external fluids. The closed-looped stability and the uniform boundedness of sta~：es are proved based on Lyapunov direct method. The robust boundary controller for reducing the vibrations of flexibk~＇ risers is developed, in which the sign function is employed to eliminate the influence of the uncertain environmental disturbances to the controller. Simulation results show that the proposed boundary controller effectively reduces the vibration displacements of the flexible risers.