A survey of linear and nonlinear consensus problems in multi-agent systems

We present the survey result of linear and nonlinear consensus problems in multi-agent systems. First, these problems are elaborated in terms of the agent dynamics, communication topology and consensus protocol. Then, the state of the art on consensus is discussed from the perspective of analysis approaches. Moreover, the essence of the classical consensus protocol is found to be a negative sub-gradient algorithm, and an approach of consensus protocol design is presented. Finally, the problems to be solved in future research directions are pointed out.