Spacecraft Attitude Control with RWs via LPV Control Theory: Comparison of Two Different Methods in One Framework

Abstract

Satellite dynamics is described by a nonlinear differential equation. Most of recent studies about attitude control have used non-linear controllers. However, with these controllers, control performance is ignored in most cases. To overcome these problems, we applied Linear Parameter-Varying (LPV) control theory to attitude control problem. To avoid difficulties coming from the nonlinearity in satellite dynamics, we modeled dynamics of spacecraft as an LPV system and applied a Gain-Scheduled (GS) controller to this model using Linear Matrix Inequalities (LMIs). In this paper, by using two methods, GS controllers are designed to guarantee overall stability and to achieve H₂ performance with distinct Lyapunov solutions. By using these controllers, 3-axis attitude control of a spacecraft with Reaction Wheels (RWs) shall be achieved. To examine how the proposed approach improves the control performance, two proposed methods shall be compared with each other.