Satellite formation flying using variable structure model reference adaptive control

In this paper a variable structure model reference adaptive control technique for spacecraft formation flying is proposed. The system consisting of a leader and a follower satellite is considered. The stability of the proposed controller is established using a Lyapunov function. Also, the robustness of the control law to non-linearities and external disturbances is presented. A reference model suitable for formation reconfiguration is then established. The performance of the proposed controller is tested through numerical simulation of the governing non-linear equations of motion and is applied for both formation keeping and formation reconfiguration. The effect of the control parameters on tracking performance and fuel consumption is examined. The effects of initial state errors, leader satellite eccentricity, constant perturbation, and differential J(2) are also considered. The numerical results demonstrate the effectiveness of the proposed control technique for satellite formation flying. In the case of the formation reconfiguration, the proposed controller outperforms the adaptive sliding mode control.