Cooperative output synchronization of networked systems in strict feedback form in the presence of unknown disturbance

This paper considers the cooperative output synchronization of networked SISO nonlinear systems that can be transferred into strict feedback form, in spite of parametric uncertainties in agents dynamics, input channel of each agent is perturbed by an unknown but bounded disturbance. Moreover, the bounds of the disturbance are also unknown. Combined Backstepping method together with Graph Theory and sliding mode control, a distributed adaptive controller is designed recursively for each agent to drive its output synchronized to its neighbors in the network while other variables in the overall system maintain bounded. It is proved that under the topology condition that the graph is connected, all agents' outputs in the network can be synchronized, i.e., cooperative output synchronization of the network is achieved. The distributed controller for each agent has five parts: parameter updaters for the unknown parameters in the dynamic of itself; parameter updaters for the parameters of its neighbors; state-feedback of itself; state information of its neighbors and an adaptive disturbance compensator. Simulation result has been presented to verify the effectiveness of the proposed controller.