Robust Control and Path Planning Algorithms for Small Satellite Formation Flying Missions

Recent advances in small, low cost satellite technology has generated a renewed interest in formation flying missions. One challenging aspect of satellite formation flying missions is collision free navigation and control. In this paper, novel robust control algorithm using Sliding Mode Control is presented for a threedimensional, high Earth orbit satellite formation scenario. The paper presents the comparison of results of three types of Sliding Mode Controllers (SMC): the first one is a tan-hyperbolic SMC, the second one is a constant plus proportional rate SMC and the third one is a power rate SMC. Hybrid propulsion system minimises the use of on-board power for close formations. Artificial Potential Field method is used for collision-free path planning of the satellites in the formation. Simulation results show that for the formation flying scenario considered in this study, the constant plus proportional rate SMC and the power rate SMC gives better performance over the tanhyperbolic SMC. Simulation results prove that for the tetrahedron formation considered in this study, the total control effort is less when the constant plus proportional rate controller and the power rate controller are used compared to the tan-hyperbolic sliding mode controller. Very little formation center movement is observed for the three SMCs.