六自由度激励台精密高刚度铰链结构设计与试验应用

Design and application of high-stiffness precision joint in 6-DOF excitation platform

精密高刚度铰链作为六自由度并联激励平台中的关键组件,其性能高低对激励台的控制精度有直接影响。针对铰链所需满足的高刚度、高基频和无间隙等要求,文章提出了基于虎克铰结构的铰链设计方法。首先根据铰链所处的工况确定选用圆锥滚子轴承作为旋转支撑部件,并通过对轴承的配置和预紧实现无间隙振动运动的要求,从而确定了铰链结构形式。然后,利用有限元法校核了结构的刚度与基频,进而完成铰链结构方案和样机制造,并将样机集成于激励台中。最后,开展了铰链动态特性试验和激励台振动控制试验,分别获取了铰链的基频和激励台控制响应。结果表明,铰链可满足激励台工作频段内的使用要求,铰链设计合理。

As a key component of the six degree of freedom （6-DOF） parallel excitation platform, the precision spherical hinge’s performance has a direct impact on the vibration control accuracy of the entire system. To meet the requirements of high-stiffness, high fundamental frequency and zero-gap for the spherical joint, a design method based on the Hooke joint structure is proposed. Firstly, according to the working condition of the hinge, a tapered roller bearing is selected as its rotary support. Then the configuration scheme and the preload design for the bearing could achieve the zero-gap movement requirement, thus the structure forms of the 2-DOF and 3-DOF joints are designed. After the static and dynamic characteristics are acquired by the finite element analysis, it is shown that the complete structural design of the spherical joint can comply with the requirements of stiffness and frequency. On the basis of this design, a prototype is manufactured and integrated into the 6-DOF excitation platform. In the dynamic characteristic test of the joint and the vibration control test of the excitation platform, the first-order natural frequency of the joint and the control response of the platform are obtained, respectively, which shows the validity of the proposed structure and design approach.