Coordinated Moving-Target Encircling Control for Networked Quadrotors With Event-Triggered Extended State Observers

Abstract

Coordinated enclosing of quadrotors for a ground moving-target is a promising enabler for exploring, self-localizing as well as autonomously navigating under challenging environments. For this purpose, this article addresses a robust coordinated target encircling control problem of networked quadrotors without the reliance on target speed and acceleration information. Two event-triggered extended state observers (ETESOs) are, respectively, constructed to allow for accurate observations toward unknown relative kinematics and lumped disturbances imposed on the rotational loop, wherein a simple event-triggered criterion is integrated to specify the sampling intervals to reduce the transmission expenditure. By resorting to the estimated items, a cooperative encirclement guidance protocol capable of achieving relative distance keeping and phase regulation is devised based on a directed graph, such that all quadrotors can cooperatively evolve along a circular orbit with a desired angular spacing, and a robust attitude controller including a compensation item of ETESO is designed to assure a precise tracking. Finally, all error variables are proved to be bounded, while the efficacy of presented algorithms is certified by simulations and experiments.