射电望远镜馈源支撑系统的振动特性

Vibration characteristics of the feed support system in radio telescope

我国正在建造世界上最大的单一口径射电望远镜,其馈源支撑系统采用刚柔串联的两级并联机构实现精调定位。该文针对Stewart并联机构运动时反作用力会引起索并联机构振动的特点,对馈源支撑系统的振动特性进行分析。将6根绳索简化成6个弹簧阻尼器,利用Newton-Euler方法建立系统完整的动力学模型,推导出系统的状态方程,提出了数值求解方法,并利用Adams仿真进行了验证。数值方法分析结果表明:Stewart动平台上负载质量逐渐增加时,索平台的振动增大,响应变慢,绳索拉力的峰-峰值与负载质量大致呈线性变化。

China is building the world＇s largest single dish radio telescope with a feed support system consisting rigid-flexible serial two level parallel manipulators to achieve fine tuning. The reaction force produced by a movement of the Stewart platform will lead to vibrations of the flexible cable-driven parallel manipulator. This study analyzes the vibration characteristics of the feed support system with the system dynamic model deduced using the Newton-Euler method by simplifying the flexible cable to a spring damping model. The system state equation is established based on the system dynamics equations. A numerical solution method is validated by the Adams method. Finally, the numerical simulations show that when the load mass on the moving platform increases, the cable platform vibrates more seriously and responds more slowly. Moreover, the relationship between the peak-to-peak value of the cable force and the cable mass is appoximately linear.