Event-Triggered Model Predictive Control of Spacecraft Formation

This paper proposes a model predictive control method based on a dynamic event-triggered strategy for high-precision formation control of spacecraft formations using continuous low thrust. An optimal formation control problem is formulated based on the J2 linear time-varying relative dynamics using the Legendre pseudospectral method, and the model predictive controller is designed based on this optimization problem. Thereafter, a dynamic event-triggered strategy is introduced in the model predictive controller, in which the optimization problem is solved only when the event-triggered condition is violated. As a result, the computational pressure of the model predictive control algorithm is greatly reduced without increasing fuel consumption or degrading control accuracy. Meanwhile, the dynamic event-triggered condition allows for relatively even event-triggered intervals, which is more conducive to engineering applications. The feasibility and stability of this control strategy are demonstrated, and the simulation results under two different formation control scenarios show that the proposed controller achieves equivalent control performance to the conventional model predictive controller, and the computational pressure is greatly reduced by designing the dynamic event-triggered condition. Note to Practitioners—This paper presents a study on an event-triggered model predictive control (MPC) strategy for spacecraft formation control. The objective is to achieve high-precision control for spacecraft formations, including formation maintenance and reconfiguration, in the presence of bounded external disturbances. The proposed control strategy significantly reduces the computational burden of the model predictive control by introducing a dynamic event-triggered policy while preserving the control performance of the MPC. Moreover, the design of event-triggered conditions effectively prevents the occurrence of the Zeno phenomenon. The feasibility, system stability, and convergence of the control strategy are rigorously analyzed, and simulation-based verification is conducted in a binary-star formation control scenario. It is important to note that the event-triggered model predictive control strategy presented in this paper is applicable to various leader-follower type formation systems, extending beyond the scope of spacecraft formation control.