考虑杆件弹性和三维间隙铰机构动力学研究

Dynamics analysis of mechanisms with elastic bars and three-dimensional clearance revolute joints

摘要:

为了能准确预测太空中可展机构的展开性能,在动力学模型中同时考虑杆件弹性和三维间隙铰的影响．间隙铰通过“T”字形杆件模拟,接触力采用非线性弹簧阻尼模型,分别考虑理想铰、三维间隙铰以及杆件弹性3种情况对可展桁架的一个单元进行展开过程数值仿真分析．设计了一个桁架单元装置,通过实验初步验证杆件弹性和间隙铰对机构动力学的非线性影响．分析结果表明间隙铰中存在径向和轴向碰撞接触力,轴向碰撞接触力影响桁架平面外稳定性,杆件弹性振动效应使能量发生转移,减小了最大碰撞接触力,加剧了轴套和销轴之间的碰撞接触次数．

Abstract:

The influences of elastic bar and three-dimensional revolute joint are considered in the dynamic model to accurately predict the deployment performance of space deployable structure. The clearance joint was simplified by “T” shaped bars and the contact force was adopted by a nonlinear elastic-damper model. The deployment process of a truss unit was simulated with the ideal joint, three-dimensional clearance joint or the elastic bar. A corresponding device was designed, the correctness of theoretical analysis was verified by the experimental result, and the dynamic nonlinear performance of truss was affected. The simulation results show that not only the radial impact contact force, but also the axial contact force exist in the clearance joint, which affect the stability out of the truss plane. Because of the elastic vibration effects of bars, energy transfer occurs, the maximum contact force is reduced, and the number of contacts between the journal and bearing is increased.