空间大型可展开环形张拉机构动力学特性分析

Dynamic Characteristics Analysis of Spatial Large Deployable Annular Tensegrity Mechanism

空间环形张拉机构是实现天线口径大型化的理想结构形式之一。为了研究环形张拉结构的动力学特性,首先介绍空间环形张拉结构的系统组成,然后对张拉结构的环形桁架进行了运动学分析。根据铰链节点的展开速度,对其展开过程进行运动规划。然后基于运动学结果建立环形桁架机构的动力学模型,通过牛顿—欧拉公式综合考虑了斜拉索索力、关节摩擦阻尼及关节锁紧力矩对动力学特性的影响,分析当机构采用无源驱动时,对斜拉索索力的影响规律。以斜拉索索力变化偏差均值及最大索力值最小为优化目标,对采用的弹簧驱动进行了优化设计,其中优化后的弹簧刚度降低了24.5%,拉索张力偏差均值及索拉力峰值分别降低了45.2%和41.6%。最后研制了缩比原理样机,进行动力学试验,通过试验结果验证了动力学分析方法的正确性。

The annular tensegrity structure is one of the ideal structural forms to make the aperture of the antenna large.In order to study the dynamic characteristics of the annular tensegrity structure,the system composition of the annular tensegrity structure is firstly introduced.Then,a full kinematic model is established.The motion planning is performed based on the velocity of the hinge during deployment.Then,the dynamics model of the hoop mechanism is established based on the results of the kinematic model.The influences of pretension forces of the cables,friction damping of the joints and the locking moments of the joints are comprehensively considered based on Newton-Euler formula.The deviation value of the pretension variation and the maximum value of the pretension are taking as optimization objectives,scroll springs when employed are optimized.The spring stiffness,the pretension variation and the maximum value of the pretension have decreased by 24.5%,45.2%and 41.6%respectively.Finally,a prototype of scaling principle has been developed,and the dynamic test is carried out.The correctness of dynamic analysis method is verified by experimental results.