Angular velocity tracking for satellite rendezvous and docking

Autonomous satellite on-orbit servicing is a very challenging task when the satellite to be serviced is tumbling and has an unknown dynamics model. This paper addresses an adaptive control approach, which can be used to assist the control of a servicing satellite to rendezvous and dock with a tumbling satellite whose dynamics model is unknown. A proximity-rendezvous and docking operation can be assumed to have three steps: (1) prior-dock alignment, (2) soft docking and latching/locking-up, and (3) post-docking stabilization. The paper deals with the first and third steps. Lyapunov-based tracking law and adaptation law are proposed to guarantee the success of the nonlinear control procedures with dynamics uncertainties. Dynamics simulation examples are presented to illustrate the application of the proposed control approach. Simulation results demonstrated that the adaptive control method can successfully track any required angular velocity trajectory even when the dynamics model of the target satellite is unknown.

► It is very difficult for a servicing satellite to rendezvous and dock with a tumbling target satellite.
► Necessary steps include matching angular velocity before docking and de-tumbling after docking.
► The paper presents adaptive control schemes to accomplish these two challenging steps.
► De-tumbling can be done even without knowing the target satellite's inertial property.