Distributed variable structure control with sliding mode for free-flying space robot

In this paper, two different distributed variable structure control methods for free-flying space robot are introduced. One is based on upper bound of disturbance, while the other is based on proportional switching. The dynamic model of the space robot, as well as the low speed friction model, is described in detail. Taking a two DOF free-flying space robot as the object, the arithmetics of the two distributed variable structure control methods are derived. The simulation results of the two methods are introduced and compared. The analysis shows that a proper variable structure control law can not only have better robustness and adaptability, but also reduce the complexity of computation.