Multi-objective and reliable output feedback control for spacecraft hovering

Abstract

A multi-objective and reliable dynamic output feedback controller design method is proposed in this paper for spacecraft hovering around targets in circular orbits. The hovering process contains two steps namely, orbital transfer and hovering maintenance. Firstly, the dynamical model of spacecraft hovering is built and multi-objective output feedback control problems for the both steps are formulated. For orbital transfer control, we focus on fuel optimization and pole placement. And H2 performance, H∞ performance and pole placement are considered in hovering maintenance control. Then, sufficient conditions for guaranteed cost and pole placement are provided in the forms of nonlinear matrix inequalities. Using some changes of variables and Schur complement, the obtained sufficient conditions can be rewritten as linear matrix inequality constraints. Likewise, sufficient conditions for H2 control, H∞ control and pole placement are presented and transformed into linear matrix inequalities. Thus, the multi-objective controller design problems for both orbital transfer control and hovering maintenance are described as convex optimizations subject to linear matrix inequalities, respectively. Finally, numerical simulations are presented to illustrate the effectiveness and validity of the proposed dynamic output feedback controller design algorithms.