Distributed Attitude Coordination Control For Spacecraft Formation Flying Under Undirected Communication Topology

In recent years,space missions fulfilled by multiple spacecraft formation flying has received a lot of research interest in the word.Spacecraft formation flying refers to a system of multiple on-orbit spacecraft within a particular formation shape on the physical space,which work as a virtual spacecraft to complete the complex mission by inter-satellite communication among the spacecraft.spacecraft formation flying gain lots of advantages,such as high reliability,low cost as well as strong flexibility compared with traditional monolithic spacecraft.Therefore,spacecraft formation flying has a wide application prospects in both military and civil fields.For some formation flying missions,the spacecraft in the formation should keep the attitudes consistent with each other in order to accomplish the given task.Firstly,the fundamental knowledge about the attitude coordination control is briefly introduced.The preliminaries include graph theory used to depict the communication relationship between the spacecraft,the corresponding matrices definition,several attitude description parameters,dynamics and kinematics model of spacecraft attitude and consensus control algorithms about typical single integral and double integral.Secondly,in order to solve the coordinative attitude H_∞ control problem of spacecraft formation flying,the attitudes and angular velocities of the spacecraft which could communicate with each other were introduced to design cooperative attitude control law based on the quaternion and the consensus algorithm.An attitude coordinated H_∞control strategy with the robustness of external disturbances is proposed base on linear matrix inequality(LMI)theory in the paper.The controller law includes the nonlinear terms in view of the performance enhancement,while the linear feedback terms is applied for the attitude coordination and stabilization.The LMI solver provided by MATLAB is applied to get the controller.It is validated by the simulation results that the control strategies can solve the spacecraft formation attitude cooperative problem and are more robust.Finally,based on the modified Rodrigues parameters(MRP)and undirected communication topology,a cooperative attitude H_∞control law is designed to solve the coordinative attitude control problem of spacecraft.The auxiliary parameter consists of attitude and the derivative of the attitude is introduced to design controller to the spacecraft formation flying with the robustness of external disturbances.The control design methods show the effectiveness in spacecraft formation with more robust by the simulation.