Abstract: The spacecraft attitude system is a nonlinear and strongly coupled system with multi-input and multi output. Basing on the nonlinear and uncertain model of the spacecraft attitude system, a fuzzy variable structure control method is proposed. The fuzzy system is used to approximate the system uncertain function. Furthermore, the errors from fuzzy approximation and external disturbances are compensated so that the influence on the system is minimized. Theoretical analysis and simulation results show that the proposed control method has high tracking accuracy and low computation load and is easy for application.

Key words: attitude control, variable structure control, fuzzy universal approximator, adaptability