Connectivity-preserving exact consensus for nonlinear multi-agent systems with unknown mixed state delays

For a class of high-order nonlinear uncertain strict-feedback multi-agent systems with limited communication ranges and unknown time-varying mixed state delays, this work proposes an adaptive fuzzy connectivity-preserving iterative learning output consensus scheme. Through an error transformation way, the initial connectivity of the digraph dictated by the communication ranges and initial positions of all followers and the leader are preserved. An appropriate Lyapunov-Krasovskii function is built to compensate the impact of time-varying delay uncertainties, and the command filter technique avoids the differential explosion problem during the backstepping process. Moreover, the uncertain nonlinear dynamics of each agent is approximated the fuzzy logic system. Then the control scheme constructed during backstepping process proves that the communication topology of the initial digraph is preserved, and the output consensus errors of all agents converge to a compact set around the origin on the finite time interval along the iteration direction. Ultimately, two experimental examples in simulation section would testify the validity of the raised consensus protocol.