Underactuated Attitude Control of Three-Body Tethered Spacecraft During Spinning for Artificial Gravity

This work studies the spinning three-body tethered spacecraft to achieve the desired artificial gravity overload. To explain the rigid-flexible coupling characteristics of the tethered system, tethers are regarded as discrete mass points to build the mathematical model. The quaternion theory is used to describe coordinate system rotation to avoid the singularity problems of tethers and tethered spacecraft. An underactuated controller is proposed to control the attitudes of sub-spacecraft during spin-up. Then, the asymptotic stability of the tethered system with attitude error is proven. To deal with the influence of unknown bounded external disturbance on sub-spacecraft attitude, a disturbance estimation function with hyperbolic cosine type is designed to suppress system chattering. In the numerical simulation, the spin-up dynamic behavior of three-body tethered spacecraft without attitude control is studied. Finally, the effectiveness and robustness of the underactuated controller are demonstrated in the simulation.