Adaptive distributed consensus for relative orbit of modular spacecrafts under a directed graph

The distributed leaderless consensus problem for relative orbit of modular spacecrafts is studied based on the consensus theory of multi-agent systems. The interaction topology among the modules is a general directed graph. When all modules are with unknown masses, we propose an adaptive control algorithm based on the information of individual module and its neighbors, without the need of relative velocity measurements. To compensate with the bounded external disturbances, we introduce a variable structure control term with an adaptive updating law. The closed-loop system is proved to be asymptotically stable. Moreover, the proposed control algorithm is totally distributed; its complexity will not increase when the number of modules becomes greater. Simulation results of a scenario of six modules are conducted to validate the effectiveness of the proposed control schemes.