Abstract: In order to reduce the chattering of variable structure control for flexible spacecraft attitude, an improved sliding mode controller is presented. Based on the boundary-layer sliding mode controller, the more smooth “arctan function” is used to replace saturation function to reduce the chattering. The delay factor is introduced in the reaching-law of sliding mode controller to reduce the maximum control torque required by the system at the initial maneuver moment, which can avoid the vibration of flexible appendages. Simulation results show that the improved sliding mode controller not only can effectively reduce chattering but also has strong robustness against parametric uncertainties.

Key words: flexible spacecraft , sliding mode control , chattering reduction , delay factor