Spinup Control of Tethered Space Station for Artificial Gravity Task * In order to overcome the problems caused by the zero gravity of space, artificial gravity space station has been widely concerned in recent years. The tetherbased space station relies on the centrifugal force generated by its rotation around the centroid to simulate gravity, which greatly reduces various problems caused by the zero gravity environment, and has many advantages such as low spin speed, flexibility, and scalability. For the spinup process of the tethered space station, a dynamic model of the tethered space station based on the Lagrange method is established firstly. Then, the control law using sliding mode theory and the dynamic inversion is proposed. Different spinup schemes are designed to test the control law. Simulation results shows that whether the systemxe2x80x99s tether retraction rate is adjustable or not, the angular velocity of the system can smoothly reach the desired value to produce the expected level of artificial gravity.

An Indirect Control Method to Stabilize Tension in the Process of Towing Transfer This paper proposes an indirect control method to stabilize tension for the tethered space system in the process of towing transfer. In the paper, the Kalman filter is designed to estimate the length of the tether and the mass of the debris under the premise that the tension can be measured. The space platform and the debris are both regarded as mass points and the tether is regarded as the massless rigid rod. On the basis of the assumptions, the tension model and the centroid dynamics model are established. And the optimal tether retraction rate is obtained by using the nominal robust model predictive control. The simulation results of our method show that the Kalman filtering method is used for quality identification, and its estimation is close to the real value. The designed control scheme has good control performance and can effectively track the tension step command.