The output feedback consensus problem of lower triangular nonlinear systems under a directed network with a switching topology is studied. It is assumed that every possible network topology contains a directed spanning tree. The proposed design method utilizes a high gain approach to compensate for triangular nonlinearity and to remove the restriction imposed on dwell time. Compared to the previous research, it is shown that the proposed control method can achieve the output feedback consensus of lower triangular nonlinear systems even in the presence of an arbitrarily small average dwell time. A numerical example is given to illustrate the effectiveness of the proposed design method.

This paper investigates the consensus problem of heterogeneous uncertain multi-agent systems with jointly connected topology, where the considered systems are composed of linear first-order, second-order dynamics and nonlinear Euler-Lagrange (EL) dynamics. The consensus protocol is designed to converge the position and velocity states of the linear and nonlinear heterogeneous multi-agent systems under joint connected topology, and then the adaptive consensus protocol is also proposed for heterogeneous multi-agent systems with unknown parameters in the EL dynamics under jointly connected topology. Stability analysis for piecewise continuous functions induced by the jointly connection is presented based on Lyapunov function and Cauchy's convergence criteria. Finally, some simulation results are provided to verify the effectiveness of the proposed methods.