I. Introduction
For some dangerous and complex tasks, a single agent is hard to complete them, but multiple agents can cooperate to efficiently and rapidly accomplish these tasks. In view of this, the cooperative control of multi-agent systems (MASs) has been successfully applied in unmanned air vehicles swarm [1] , distributed sensor networks [2] , intelligent traffic and transportation systems [3] and so on. Consensus, as a fundamental cooperative control problem, has received tremendous attention from academia and industry [4] – [9] . Li et al . [4] took into account the consensus problem of linear MASs, proposed consensus protocols based on the relative information among agents by combining adaptive control and event-triggered control approaches, and discussed the influences of external disturbances. In [6] , Wei et al . put forward a type of directed MASs with stochastic external disturbances, and gave a consensus criterion by choosing suitable adaptive control protocol.