Fully distributed and velocity-free multi-agent source localization under model-based/model-free scalar fields

In this paper, we explore the fully distributed source localization for double-integrator agents in both model-based and model-free scalar fields. In the absence of velocity information, a novel prescribed-time velocity observer is designed relying on double-integrator dynamics. In consideration of unavailable field gradients, gradient estimators with parameter adaptation strategy are developed for model-based and model-free scalar fields, respectively. Coupled by velocity observers, gradient estimators and auxiliary variables, we propose cooperative event-triggered formation control schemes for agents in a fully distributed way. Further, the formation center of agents is driven toward the field source. Based on the Lyapunov principle and nonsmooth theory, we analyze the stability of the closed-loop system and exclusion of the Zeno phenomenon in theory. Ultimately, the feasibility of the proposed control schemes is verified by numerical simulation under field model-based and model-free cases, separately.