Robust Control of Rigid-Body Attitude System with Guaranteed Cost: A Linearization-Free Method

This paper is concerned with the guaranteed cost control issue of nonlinear rigid-body attitude systems under parameter uncertainty. By exploiting the nonlinear attitude dynamics characterized by quaternions, a novel mechanism for system analysis and synthesis is proposed, which is different from most of the existing guaranteed cost attitude control results. The mechanism enables attitude systems to achieve robustness and guaranteed cost performance. It is highlighted that the proposed method performs controller design with linear matrix inequality constraints, independent of model linearization, which can explicitly deal with the nonlinearity in attitude systems and then avoid modeling error. A numerical example is taken to validate the efficacy and advantage of the proposed method.