考虑铰链间隙的水面并联稳定平台动力学分析

Dynamic Analysis of Offshore Parallel Stabilized Platform in Considering Joint Clearance

针对某小型浮式稳定平台结构紧凑、负载惯量大的特点,设计了一种以少自由度并联机构为基础的改进型串联与并联机构。根据该平台的结构特点,进行了运动学分析,推导了系统雅可比矩阵,并利用Lagrange方法建立了平台的动力学模型,分析了平台的动力学特性。为分析含间隙的支链受力,将其简化为刚体—弹簧模型,通过改进的Hertz接触理论,采用非线性弹簧阻尼模型计算接触力,最终建立了含铰链间隙的平台动力学模型。数值计算与实验结果表明了数据建模的有效性,同时铰链间隙对动平台的位置精度和动力学特性产生了显著影响,对平台结构产生了较强的冲击。

An improved serial-parallel mechanism based on less DOF parallel mechanism is designed for a floating stabilized platform with compact structure and high load inertia. Based on the structural charac- teristics of the platform, the kinematics is analyzed, the system Jacobian matrix is derived, and a dynam- ic model is established and analyzed by using Lagrange equation. A simplified rigid body-spring model is proposed to analyze the chains with clearance joints. A non-linear spring-damper model is introduced to calculate the contact force by using improved Hertz contact theory, and a dynamic model considering joint clearance is established. The numerically computated and experimental results show that the dynamic model is effective, and the clearance has significant impact on the structure, position accuracy and dy- namic characteristics of moving platform.