Optimization And Design Of A Parallel Platform Combined Vibration-isolation With Pointing

The equipment,such as reaction wheel assemblies,propeller,attitude gyroscope and solar panel deployment actuators,are the base installations of a spacecraft.They will produce multi-dimensional micro-vibration.Micro-vibration has the features of wide bandwidth and small amplitude.Which seriously affect the imaging quality of the high resolution space telescope.A common solution is to isolate the space telescope from the vibration source.Meanwhile,in order to ensure the accuracy of the imaging of space telescope,the position of the secondary mirror need to adjust.Pointing system and vibration isolation system are need simultaneously.At present,the two systems are independent of each other in space telescopes and other engineering applications.The purpose of this paper is to integrate the pointing function and vibration isolation function into a multi-degree-of-freedom parallel platform to reduce the volume and quality of the equipment and save the cost,which is very important for the development of space remote sensors.Firstly,parallel mechanisms based on Gough-Stewart platform is researched,and Cubic configuration is adopted,which can minimize the coupling of six degrees of freedom motion.The characteristics of kinematics and dynamics of the 6-DOF parallel platform are studied.Kinematics model of the platform is built and the dynamics model of the platform is established by Kane method.Then,the dynamic characteristics of the parallel platform are analyzed by finite element method,including the analysis of the axial stiffness,radial stiffness of drive legs and the natural frequency of the platform.Finally,the axial stiffness of drive legs and the dynamic characteristics of the whole platform was tested.In the structural design,firstly,the actuator of the leg is compared,then,the voice coil motor is used as the driving motor.The hinge,which is directly affecting the precision of the parallel mechanism,is designed.Flexible hinges are adopted in order to reduce the mind and non-liner error.The upper platform is analyzed and compared,and the scheme of reducing the platform quality is adopted in order to improve the natural frequency of the parallel platform.Secondly,the leg of platform equipped with two leaf springs,the leaf spring is adopted the best solution after a number of analysis,in addition,completed the design of connecting rod,inhibiting device,air flotation equipment,and selected suitable linear displacement sensor and so on.