Huiqin Pei Hongli Xiao Fault-tolerant group consensus control for hybrid multi-agent systems by observers and event-triggered strategy. 108320 2026 363 J. Frankl. Inst. 2 https://doi.org/10.1016/j.jfranklin.2025.108320 db/journals/jfi/jfi363.html#PeiX26 streams/journals/jfi