Distributed Attitude Cooperative Control Of Spacecraft Formation Based On Consensus

With the rapid development of aerospace microelectronic technologies,the working mode of the spacecraft formation flying system composed of multiple micro-nano satellites has gradually become the main development direction of spacecraft.Compared with the traditional single large spacecraft,spacecraft formation flying has stronger system performance,higher reliability and better flexibility,and has great application value in the fields of Earth monitoring and deep space exploration.Attitude coordinated control is a key technology to ensure the smooth realization of formation flying missions,and has received extensive attention from researchers.Combining the application demands of spacecraft formation flying,this dissertation deeply studies the distributed attitude coordinated control problem of spacecraft formation in the case that only a subset of formation spacecraft can obtain the desired attitude,there are external disturbances and model uncertainties,and energy and computing resources are limited.The main research contents are as follows:For the spacecraft formation system where only a subset of formation spacecraft can obtain the reference attitude,under the ideal condition without considering the disturbance,an attitude cooperative control algorithm based on feedback linearization is designed to ensure that the system state errors can converge to zero cooperatively.In addition,it can be proved by Lyapunov theory that the formation system is asymptotically stable under the attitude coordinated controller.The robust attitude coordinated control problem under the influence of unknown external disturbances and model uncertainties is studied.First,when the upper bounds of disturbances and states can be obtained,an attitude coordinated control method based on sliding mode control is designed to suppress the influence of disturbances on the formation system.Furthermore,combined with the nonlinear disturbance observer technology,an attitude coordination control strategy based on nonlinear disturbance observer is proposed to improve the control accuracy of the closed-loop system.Then,under the condition that the upper bounds of disturbances and states are unknown,the adaptive control technology is used to improve the robustness of the formation system to disturbances.Considering that the initial disturbance estimation value generated by the disturbance observer may be much larger than the actual disturbance value,variable structure control technology is used to avoid the introduction of large disturbance estimation errors,and an attitude consensus control algorithm based on adaptive control and variable structure control is designed,which significantly improves the robustness of the formation system while ensuring that the control system has high control accuracy.The finite-time attitude coordination control problem in the presence of external disturbances and model uncertainties is studied.First,under the condition that the upper bounds of states can be obtained,a finite-time attitude cooperative control scheme based on nonsingular fast terminal sliding mode is designed to ensure the rapid convergence of the formation system.Furthermore,a finite-time sliding mode disturbance observer is designed to quickly observe external disturbances and model uncertainties of the formation system,and the finite-time attitude coordinated control method is improved on this basis.Then,under the condition that the upper bounds of states are unknown,based on adaptive control and variable structure control technologies,a finite-time attitude consensus control strategy with strong robustness is designed to improve the convergence rate of the control system and avoid the introduction of large observation errors of the sliding mode disturbance observer,which ensures that the formation system has strong robustness to disturbances.Considering that energy and computing resources of formation spacecraft are limited,the distributed attitude coordinated control method via event-triggered control is studied to save energy and computing resources of the formation system.First,under the undirected communication topology and without considering external disturbances and model uncertainties,an event-triggered attitude coordination control method without continuous update is proposed,which effectively reduces the update frequency of the attitude coordination controller,thereby saving formation system resources.Then,under the directed communication topology and considering external disturbances and model uncertainties,an event-triggered attitude coordinated control algorithm based on sliding mode control is designed,which significantly reduces energy consumption and computational burden of the formation system while maintaining good control performance.Moreover,the proposed event-triggered function has a strictly positive minimum inter-event time,which excludes the possibility of Zeno phenomenon.