海上漂浮2-HUS/U并联平台动力学分析

Dynamic Analysis of Offshore Floating 2-HUS / U Parallel Platform

针对小型化、灵活投放海上漂浮平台的平衡稳定控制需求,提出了一种具备空间二维稳定的2-HUS/U并联平台,其HUS支链为驱动支链,U为恰约束从动支链,采用滚珠丝杆驱动机构。设计的2自由度无冗余结构,为平台的快速稳定平衡提供保证,采用螺旋理论分析验证了2-HUS/U并联平台自由度;根据平台的约束方程导出了位置逆解和Jacobian矩阵,分析了平台的速度、加速度特性和可达工作空间,利用刚体的拉格朗日方法对该平台进行了动力学分析。通过数值算例对并联平台的运动学和动力学分析结果进行了数值求解。结果表明,该平台具备三级波浪10°/s波频的调平能力,满足三级波浪10°波倾角的稳定需求;在45°波倾角和10°/s的波频下,负载需求驱动力为15 000 N,满足海上漂浮平台高负载的驱动需求。通过系统整体的分析,表明所提出的海上平台满足三级海洋环境的需求。

For the balance and controlling demand of the small and flexible delivery offshore floating platform,a 2-HUS / U parallel platform was presented and it had space two-dimensional stable ability,which adopt ball screw mechanism. Its HUS-limps were regarded as the driver and U-limp was regarded as the driven. It provided a guarantee for the fast and stable balance of platform,and the degree of freedom of the platform was verified by the screw theory. According to constraint equations of platform,the reverse solution and the Jacobian matrix of the platform was derived and its velocity,acceleration performance,and reachable workspace were analyzed. The whole dynamics of space parallel platform was analyzed by the Lagrange ＇s formulation. The results of kinematics and dynamics analyses of parallel platform were solved as numerical example. The results show that the control of stability and balance is easily achieved by platform of less freedom. The platform has the stable ability of three-wave frequency of10° / s,and meets the stable demand of three-wave angle of 10°. The maximum tilt angle of platform is12°,and the workspace is symmetrical about the center axis. In the wave angle 45° and wave frequency10° / s,the driving force for load is 15 000 N,and the platform meets the high load need of offshore floating platform. Through the whole analysis,it proves the offshore platform proposed meets the demand of three-wave environments,and it also proves certain theoretical basis for the platform optimization and control system design of such platforms.