State-dependent boundary layer method for attitude control of satellite

Sliding mode control is known to be robust against parameter uncertainties and external disturbances. based on the dynamic equation of motion,a sliding mode controller is designed to solve this problem. however,for the sliding surface to be attractive,a switching function is used in the control law,which caused chattering of the control signal. in order to avoid this,a boundary layer method is considered in the modified controller. so this paper proposes new boundary layer designs that resolve the problem in control accuracy and control signal smoothness in sliding mode control. the propose design improve the system state to almost zero with no chattering in the control signals. © 2015 penerbit utm press. all rights reserved.