Distributed Time-varying Coordination of Uncertain Nonlinear Multi-agent Systems: A Unified Model Reference Scheme

University Of California-Riverside, Riverside CA

Investigators

Abstract

Distributed coordination of multi-agent systems has numerous applications. Existing research on distributed multi-agent coordination is often limited to static problems, while time-varying problems can respond to moving objects of interest and real-time changes in the environment/missions (for example, coordinated exploration, cooperative monitoring, cooperative transport, region-following formation tracking, and multi-robot multitarget navigation) but are more challenging. In reality, multi-agent systems often exhibit nonlinearity and uncertainty but corresponding results are limited. Addressing the two aspects (distributed time-varying coordination and uncertain nonlinear agent dynamics) simultaneously will substantially enhance the existing functionality of multi-agent systems. Unfortunately, the interwoven challenges caused by the two aspects are often intractable, not to mention further complexity due to switching graphs and partial measurements. A systematic approach to tackle the two aspects simultaneously is lacking. This project aims at deriving a novel model reference coordination scheme to bridge the gap between distributed coordination of linear systems and tracking control of a single uncertain nonlinear system. Education and outreach activities will broaden participation of underrepresented groups in research. The objective of this project is to derive a novel unified model reference coordination scheme combined with new inverse backstepping thinking in design to systematically address distributed time-varying coordination of uncertain nonlinear multi-agent systems. In the proposed scheme, each agent’s reference model is chosen as a linear system driven by distributed time-varying nonsmooth nonlinear coordination terms defined by physical states between neighbors (e.g., relative state/output measurements). Distributed time-varying coordination of uncertain nonlinear multi-agent systems is divided into three parts: i) coordination of the reference models themselves; ii) tracking of the state/output of each agent's reference model by with uncertain nonlinear dynamics; iii) study of mutual influence/feedback of the first two parts. The PI will explore the usage of the scheme to accommodate various uncertainties and dynamics and address distributed time-varying coordination with nonsmooth nonlinear algorithms accounting for unavailable information and heterogeneous uncertain systems of different types and orders. The proposed research will solve challenging open research problems and advance the state of the art in distributed multi-agent coordination. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.