Multiple Spacecraft Formation Control Using

Multiple spacecraft formation control about the 2 L libration point is investigated in this paper. The circular restricted three-body problem with Sun and Earth as the two primaries is utilized as a framework of study. The idea of virtual structure is considered as the architecture of multiple spacecraft formation. The center of the virtual rigid body follows a nominal orbit around the 2 L libration point. The individual spacecraft is controlled so as to keep a constant relative distance from the center of the virtual structure. A nonlinear model is developed that describes the relative formation dynamics. This nonlinear control problem was addressed by employing a relatively new nonlinear control approach, called the θ D technique. This method is based on a series solution to the Hamilton_Jacobi_Bellman equation and gives a closed-form suboptimal feedback solution. Simulation results demonstrate that this controller is able to provide millimeter-level formation flying accuracy. Copyright © 2005 IFAC