Integral sliding mode controller design for near space vehicle with input constraints

Near space vehicle (NSV) is a nonlinear, multivariable and strongly coupled system. During the arbitrary trajectory tracking of NSV, the employment of conventional sliding mode variable structure control often results in steady-state errors, if there is some certain external disturbance. In this paper, an integral sliding mode variable structure controller is designed to eliminate the steady state error. Since the inputs of most actuators are restricted, the control performance will deteriorate or fail when the control signals are input directly into the controlled object. Therefore, the saturation limit is introduced to the controller design process to limit the input. Finally the proposed control scheme is applied to the attitude motion mode of the NSV and the simulation results confirmed its effect.