Abstract: By using Kane method, a mathematical model with CMGs as actuators was built for the three-axis satellite with flexible appendages. An active-disturbance-rejection sliding mode controller was designed for the demand about quickness and stability in attitude control. This controller observed the disturbance by expanded state observer, and compensated the output. The slide mode method in the controller made the system quick and stable. The simulation experiments show that the controller could control the attitude of three-axis satellite efficiently and weaken the vibration of flexible solar panel. The active-disturbance-rejection sliding mode controller shows the merits of both active-disturbance-rejection method and sliding mode method. It is better in the quickness than traditional PID and sliding mode controllers. It would be valuable to be applied in the attitude control of satellite.

Key words: three-axis satellite, flexible appendage, active-disturbance-rejection control, sliding mode