Design And Analysis Of Satellite Ground Simulator With Disturbance Free Payload

With the development and application of space missions,there are increasingly high requirements about control accuracy of artificial satellites.The structure of satellites is improved based on the disturbance free payload structure.The whole satellite is divided into two parts,the support module and the service module.This two modules are connected with many non-contact actuators and displacement measurement sensors,which could help decrease vibration transmissibility.Satellite with payload module an d support module is also called satellite with disturbance free payload.This paper designed the fundamental structure of satellite ground simulator with disturbance free payload in order to achieve the requirements of relative position control and vibration isolation.First of all,the paper proposed several design objectives about the satellite ground simulator with disturbance free payload.Then introduced the mechanical structure of the disturbance free payload simulator,including the payload module,support module and the middle part connects them.The dynamic model s of the payload module and support module in the system coordinate are built respectively to help analyze the active control model.Besides,the measurement results of 3-axis accelerator is processed based on the system coordinate to guarantee the accuracy of vibration isolation analyses in one degree of freedom.Secondly,the purpose of constructing satellite ground simulator with disturbance free payload is to achieve relative position control and vibration isolation.The control method of each function is designed based on analyses.The relative position control between payload module and support module is achieved by relative displacement negative feedback.For the active vibration isolation control between these two modules,several control methods of different feedback variables are analyzed.After comparison,the relative displacement negative feedback is chosen to execute active vibration isolation.According to the simulation results,the relative displacement negative feedback method could improve the vibration isolation performance in theory.Finally,the whole system of satellite ground simulator with disturbance free payload is constructed including hardware and software.The relative positon control experiments and vibration isolation experiments in single degree of freedom are conducted respectively.According to the results of relative position control,the displacement resolution in X and Y direction are 10?m,and the angle resolution in Rz direction is 4.14?,which corresponds with system resolution requirements.According to the results of vibration isolation,in the frequency range from 1Hz to 100 Hz,the vibration transmissibility is decreased in both X direction and Y direction.The vibration transmissibility in X direction could achieve-20 d B when the vibration frequency is higher than 50 Hz.The vibration transmissibility in Y direction could achieve-20 d B when the vibration frequency is higher than 30 Hz.