Self-docking capability and control strategy of electromagnetic docking technology

Electromagnetic docking technology has lots of advantages, such as no propellant consumption and plume contamination, as well as continuous, reversible and synchronous controllability, ensuring a broad prospect of application in regular on-orbit servicing missions. However, the advantages come at the cost of inherent highly nonlinear and coupled dynamics, and the far-field electromagnetic force/torque models are uncertain because of the gradually decreasing relative distance, making the control problem very challenging. From the daily phenomenon of automatic magnetic attraction and some similar results of electromagnetic experiments, this paper firstly attempts to study the self-docking capability of electromagnetic docking technology, from ground research to on-orbit research with both theoretical analysis and simulation verification. Making advantage of the self-docking capability, the paper secondly studies the control strategy to better resolve the inherent control problems. A novel control strategy that combines the merits of Artificial Potential Function Method (APFM), Lyapunov theory and Extended State Observer (ESO) is put forward, and a simple coplanar docking example is presented. Theoretical analysis and simulation results verify the existence of self-docking capability, as well as the feasibility of this novel control strategy.

► Find and conclude the advantages and the costs of electromagnetic docking technology.
► Verify the existence of self-docking capability of electromagnetic docking technology.
► Give and verify the existence conditions of self-docking capability.
► Develop and verify a novel control strategy based on APFM, Lyapunov theory and ESO.