Reaching law-based SMC for spacecraft applications with actuators constraints

This letter considers a robust sliding mode control method for a spacecraft attitude control. The design of the control law is based on the reaching law approach for continuous-time systems. A novel method is proposed to design the parameters of both the reaching law and the sliding surface. The reaching law ensures that during the reaching phase the states of the system remains bounded. Then, taking into account the parameters of the mathematical model, the bounds are defined so that the control law does not overload the actuator limits, whatever the initial conditions. Furthermore, a variable gain is considered for the control law, to provide chattering alleviation of the control input. Numerical simulations are performed to show the effectiveness of the proposed approach.