VSC reliable design with application to spacecraft attitude tracking

This study investigates variable structure reliable control issues of nonlinear systems and its applications to spacecraft attitude tracking problems. Both passive and active reliable control laws are proposed using variable structure control (VSC) technique. The passive one must know which group of actuators is allowed to fail, while the active one must accompany a fault detection and diagnosis (FDD) scheme. Both the reliable controllers need not the solution of Hamilton-Jacobi equation or inequality, which are essentials in optimal approaches such as reliable LQR and H_infin designs. As a matte of fact, the VSC approach is able to relax the computational latency in control law computing. The proposed reliable designs are also applied to spacecraft attitude tracking problems to explain their effectiveness and benefits. Finally, simulation results and comparisons between LQR and VSC reliable designs are given to illustrate the merits of the proposed scheme