Optimal Reconfiguration Control of Electromagnetic Spacecraft Formation Using Gauss Pseudospectral Method

This paper presents the concept of electromagnetic satellite formation flight (EMFF), a novel propulsion mode of controlling the relative motion of satellite formation without propellant consumption. The alternative actuation system utilizes electromagnetic force, generated by the interaction of electromagnets around component spacecrafts, to transform the configuration. The linear equation of relative motion and stable analytical solution for circle reference orbit are then established. The optimal reconfiguration problem of a two-spacecraft electromagnetic formation in low earth circular orbit is solved using optimal control techniques. The objective of the reconfiguration is to maneuver the formation between two stable elliptic configurations based on CW equation. The optimality criteria considered is minimum time. Gauss pseudospectral method is applied to convert the problem into nonlinear programming (NLP) which can be solved by sequential quadratic programming (SQP). Numerical simulation indicates that the Gauss pseudospectral method can effectively converge to optimal solution, and it can be applied to other non-contact forces satellite formation. It also proves that the electromagnetic actuation technology is feasible for satellite formation reconfiguration.