Chattering Free Distributed Event-triggered Adaptive Attitude Synchronization of Multiple Spacecraft with Positive Minimum Inter-event Times

The attitude synchronization control problem of multiple uncertain spacecraft with event-triggered communication is an interesting research topic. However, the existing results are difficult to ensure the positive minimum inter-event times (MIETs) while achieving asymptotic convergence performance. Besides, the drawback that the controllers of the spacecraft suffer from chattering may exist, due to the transmitted discontinuous neighbors' states. To overcome the difficulty and drawback, two novel distributed adaptive control strategies are presented under event-triggered communication condition. Specifically, we first consider the attitude synchronization convergence. To estimate the final synchronization value of the attitude while avoiding the undesirable chattering phenomenon of the controllers, a distributed attitude filter with event-triggered state transmission is presented for each spacecraft, which can generate a continuous reference signal for each spacecraft. To ensure the positive MIETs, a novel triggering condition is designed, by resorting to a clock-like variable. Based on the attitude filter and triggering condition, a distributed adaptive attitude synchronization control scheme is presented.Then, we further generalize the design idea to consider the attitude synchronization tracking of a stationary leader, where a distributed event-triggered adaptive attitude tracking control scheme is proposed. Finally, simulation results are provided to validate the effectiveness of the proposed control strategies.