Model and Control of Satellite Formation Flying

Abstract

The topic of this thesis is model and control of formation flying for satellites. The focus is on formation of the satellites that has a leader-follower structure. The goal for the satellites that are in different positions, is to arrive in the same orbit and get near each other as close as possible. This is also known as a rendezvous.

In this thesis both the linear model and the nonlinear model for relative motion have been derived, by deriving the equations of motion for the follower satellite relative to the leader satellite. For the linear model the Hill-Clohessy-Wiltshire equations are presented and used for deriving control laws for formation flying. For the nonlinear model, a controller is developed using the nonlinear equations of motion for relative motion and investigated for formation flying. Relevant perturbations are included in the model.

Four different control laws are derived and implemented, where three of them are linear controllers. There are simulations performed for each of the controllers to show how they work for different scenarios.

It is concluded that the linear control laws work well for formation flying, but the nonlinear controller developed does not work at this point, and needs to be developed further.