Abstract:

In order to realize the hovering and the attitude directing to characteristic point on disabled satellite at the same time, the relative dynamics and control between the characteristic point and the chaser were researched. The coupled position and attitude dynamic model was built under the chaser’s body frame. Combined with the kinematics of characteristic point, specific point, the expected position and attitude of the chaser were derived. considering the chaser’s mass, moment of inertia uncertainty, system’s disturbing force and disturbing moment uncertainty, and the moment of inertia uncertainty of the disabled satellite, an adaptive control law was designed, and the closed-loop system was proved to be stable through Lyapunov method. If there were constraints for the output, the process for adjusting the control parameters was designed and the output values were limited. The numerical simulation shows that the system can complete the tracking mission with position error1cm and attitude error 0.01° under the designed control law With the increasing of uncertain parameter’s deviations, the position error is raised to 7cm while the attitude error is raised to 0.1°. To adjust the control parameter and limit the output’s value, the control force and control moment can be restrained in the expected range while the tracking accuracy does not change, and the control required impulse can be reduced 9% while the required impulse moment can be reduced 30%.

Key words:

disabled satellite, coupled position and attitude, position and attitude tracking, adaptive control, model uncertainty