Event-Triggered Attitude Coordination Control of Heterogeneous Spacecraft Cluster With Input Constraints

This study addresses attitude coordination in on-orbit assembly of heterogeneous clusters comprising rigid and flexible spacecraft. Two core challenges are tackled: 1) the inherent heterogeneity in dynamics models between rigid and flexible spacecraft complicates unified attitude coordination while introducing nonnegligible vibration effects, and 2) under limited communication and control capabilities of the cluster, the current event-triggered schemes embedded in input channels potentially fail to balance dual constraints between communication load and actuator response burden. To address aforementioned issues, first, two auxiliary variables are introduced to homogenize the attitude control models of rigid and flexible spacecraft, enabling shared event-triggered mechanism and control law. This unified framework achieves synchronized attitude coordination and concurrently suppresses vibrations of flexible spacecraft. Second, the proposed event-triggered control scheme incorporates control torque amplitude and rate constraints to prevent control signals from updating as high-amplitude step signals at triggering instants, thereby reducing actuator response burden. Comparative analysis with an advanced dynamic event-triggered scheme demonstrates that the proposed heterogeneous attitude coordination strategy smooths jagged control inputs without increasing triggering frequency, balances communication load and actuator response burden, and achieves faster attitude synchronization with higher convergence accuracy.