CONTROLLER DESIGN BASED ON SIMILAR SKEW-SYMMETRIC STRUCTURE FOR NONLINEAR PLANTS

This paper proposes a novel controller design approach for nonlinear plants. A class of stable nonlinear systems with a similar skew-symmetric structure is chosen as the objective closed loop system, and two design methods are proposed with backstepping and direct construction. Compared with the conventional back-stepping, method, the proposed backstepping method need not construct a Lyapunov function step by step, thus the design procedure is simplified. The direct construction method can be applied to some nonlinear plants for which the conventional backstepping is not feasible; and the design call be accomplished in only one step. Furthermore, for some nonlinear plants which have a lower triangular Structure with two subsystems, simpler controllers can be derived by the proposed direct construction method than those derived by backstepping design. In addition, the proposed methods are both system structure oriented, therefore their designs are more intuitive than the conventional backstepping design. Two controllers are derived for satellite attitude control by employing the proposed methods simulation results demonstrate their effectiveness.