Dynamics And Control Of A Spinning Three-body Tethered Formation System

In the recent decades,the tethered formation system has attracted a lot of attention for its high maneuverability,wide scope of observation and short development cycle.More and more scientists have been putting efforts into the stability maintaining,the control of tether deployment or the ground-based experiments of tethered formation systems.Therefore,it has been quiet popular to study the maintaining and controlling of on-orbit tethered systems.What’s more important is to build an effective ground-based experimental platform to do verification of the theories for the tethered formation systems.This paper will focus on a typical kind of there-body tethered formation system which spins in space.The main points are as follows:First,modeling the there-body tethered formation system in a non-inertial coordinate of which the origin point is in the system’s center of gravity.The dynamical response will be studied in this coordinate,and there will come a conclusion of the minimum spinning speed to maintain the stability.The conclusion will be proved with the Floquet theory.After that,the effects of the perturbations will also be studied.Second,there will be a comparison of three deployment methods which are deploying freely,deploying in a constant speed and deploying in a slowing-down speed.Deploying freely is to release the tether by the spinning of the system,deploying in a constant speed is to use a mechanism to keep the tether deploying in a certain speed and the last method will use the jet force to slow down the speed of deployment.Last but not least,a ground-based experimental platform is introduced to simulate the environment in space and to verify the formation stability rules above.In this experimental platform,the air-bearing test-bed is used to make a frictionless environment and the jet force will be used just like the real spacecraft in the outer space which can make the simulation more convictive.