LMI-based Mixed H₂/H_∞ Control with Regional Constraints for Spacecraft Attitude Tracking

Abstract

Satellite dynamics is described by a nonlinear differential equation. Most recent studies about attitude control have used nonlinear controllers. However, with these controllers, control performance is ignored in most cases. To overcome this problem, this paper applies the linear parameter-varying (LPV) control theory to the attitude control for a spacecraft with reaction wheels (RWs). The LPV control theory can provide a gain-scheduled (GS) controller by using linear matrix inequalities (LMIs) for the mixed H₂/H_∞ control which guarantees optimality and robustness at the same time. Besides, two types of regional pole placement (RPP) constraints are considered. Through some numerical examples, the effectiveness of these two types of RPP constraints are demonstrated.