On Consensus of Multiagent Systems with Input Saturation: Fully Distributed Adaptive Antiwindup Protocol Design Approach

Input saturation is a quite common phenomenon when implementing a controller. Failing to deal with the effect of input saturation may cause failure of the control tasks. This article develops fully distributed adaptive protocol design approaches for consensus of multiagent systems subject to input saturation with local output information. By introducing an extra internal state as the antiwindup compensator for each agent, two types of fully distributed adaptive protocols are presented, namely, edge-based distributed adaptive antiwindup protocol and node-based distributed adaptive antiwindup protocol. For the case with absolute output information, to further reduce the order of the protocols, the local observer as well as the integrated distributed antiwindup observer are designed, based on which a fully distributed edge-based adaptive antiwindup protocol is presented. Such an integrated observer suitable for the node-based protocol is also proposed, and the corresponding fully distributed node-based adaptive antiwindup protocol is then given. The discussions on the difference among the protocols designed in this article are also elaborated. The main feature of the presented protocols is that an extra term is introduced in the controller as the compensator, which plays a fundamental role in effectively tackling input saturation. The protocols given in this article depend only on local output information of each agent, without any use of eigenvalue information of the Laplacian matrix associated with communication topologies, and thus, are all fully distributed.