Relative position and attitude coupled controller design for approaching and docking with a freely tumbling target

Relative position and attitude coupled control algorithm combined with sliding mode and adaptive control techniques is developed for an approaching and docking autonomously system, in which the unexpected disturbances and configuration uncertainties are considered explicitly. It is noted that the proposed controller can rigorously enforces actuator-magnitude saturation constraints and make the closed-loop system attenuate the disturbance with L₂ gain. The associated stability proof is constructive and accomplished by the development of a novel Lyapunov function candidate. Numerical results show that this method achieves good tracking performance under the multi-constraints mentioned above.