A hierarchical design framework for distributed control of multi-agent systems

In this paper, a hierarchical design framework is proposed for distributed control of multi-agent systems. Different from the traditional distributed design philosophy that directly couples the agents' cooperation and individual regulations, the proposed framework decouples these regulations and separates the distributed control design into two layers, i.e., the layer of reference signal generator design and the layer of tracking controllers design. Specifically, the nodes of the generator play the roles of some virtual agents that achieve the distributed control goal and the agents' tracking controllers are used to track the reference signals produced by the generator. The novel design framework makes the agents reach the distributed control goal well and it has better design flexibility/practicality and stronger versatility/scalability. To demonstrate these advantages, two types of representative examples on hierarchical design are exhibited for multi-agent systems with mismatched disturbances and those with communication/input delays, respectively. All examples confirm that the proposed design framework is a natural choice in the presence of some complex factors, which provides not only simpler design but also more autonomy to the agents.