Intelligent adaptive variable structure attitude maneuvering control for flexible spacecraft with actuator saturation

In this paper, neural network (NN) based robust controller for rotation maneuver is considered for an orbiting flexible spacecraft, taking into account the actuator saturation. The actuator saturation is assumed to be unknown and treated as the system input disturbance. With the universal approximating property and learning capability of NN, the NN-based saturation compensator is design and inserted into a feed-forward to compensate the saturation nonlinearity. Then an adaptive variable structure controller, which only uses the output information, is designed to reject the disturbance, deal with uncertainty and ensure that the system trajectories globally uniformly ultimately bounded, in which need for knowing the system parameters in advance is eliminated by using an adaptive update technique. Systematic design procedure is also developed for synthesis of the NN adaptive variable structure attitude control strategy. To study the effectiveness of the corresponding control scheme, the traditional methods are also developed for the control system. Both analytical and numerical results are presented to show the theoretical and practical merit of this approach.