Nonlinear consensus algorithms for second-order multi-agent systems with mismatched disturbances

In this paper, the consensus control problem is investigated for second-order multi-agent systems encompassing mismatched disturbances. By integrating both sliding-mode control (SMC) and disturbance observer based control (DOBC) approaches together, a composite consensus control strategy is proposed. In the first step, for each agent, a nonlinear disturbance observer is developed to estimate its mismatched/matched disturbances. In the second step, by involving the mismatched disturbance estimates, novel sliding-mode surfaces are designed for both leaderless and leader-follower cases. Finally, based on such surfaces, sliding-mode consensus protocols are proposed for both cases, which guarantee global asymptotical stability for the closed-loop systems. Simulation results demonstrate the effectiveness of the proposed consensus algorithms.