Design And Aanalysis Of The Six-degree-of-freedom Vibr Ation-isolation Platform

CMGs(control moment gyroscopes) or flywheels are responsible for the position and posture regulating of high-resolution satellites. Meanwhile, the high-frequency micro-vibration, which is generated when CMG is working, will affect the pointing precision of the payload, the resolution, the stability, etc. It is becoming increasingly important to restrain the micro-vibration of spacecraft. Therefore, Designing the six-degree-of-freedom vibration-isolation platform by combination the technologies of parallel platform and vibration-isolation is of vital importance.This thesis systematically studies spacecraft's vibration of six degrees of freedom. Besides, through the theory model, the simulation analysis and the experimental validation, the technology of six-degree-of-freedom passive and active vibration-isolation is deeply studied. The main work of the thesis is as follow:1. The kinematics is analysed for the six-degree-of-freedom parallel platform. Using the force Jacobian matrix, mechanism parameters of the platform is optimized, which providing the foundation for mechanism design. Kane method is used to generate the kinetic equations of the platform. This makes the equations simple and normal, which is beneficial to calculation and analysis.2. According to the results of analysis, the six-degree-of-freedom platform is redesigned. The springs, flexible ball joins, flexible hooke joints and some other components which could be in relatively large deformation. Then, rigid flexible coupling model is generated. Finally, using MSC.Fatigue to implement virtual fatigue experiment at key components through total life analysis.3. Both the passive and the active-passive vibration isolation are simulated to verify the vibration-isolation performance of passive vibration-isolation system. For the relatively low frequency vibration, the active vibration-isolation technology is introduced and co-simulation model is generated. Moreover, active vibration isolation is controlled by fuzzy PID controller which can adaptively regulate the control parameters of active vibration isolation.4. According to the theory model, the physical prototype of the six-degree-of-freedom vibration-isolation platform is produced. To meet the requirements of the vibration-isolation experiments, Suitable experimental materials are chosen. Then, pure passive vibration-isolation experiment of the separate leg is conducted according to the experimental scheme, verifying the vibration-isolation performance to of the platform.