Differentiator-based bearing-only formation control of quadrotors

This article addresses the leader-follower formation control problem for a group of quadrotors using only relative bearing measurements. Most existing methods require full position or velocity information, which cis challenging to obtain in harsh environments. In contrast, the proposed control scheme is based on a hierarchical system that does not rely on relative position or velocity measurements. The bearing-only control law is designed to stabilize the desired formation, and each quadrotor maintains predetermined bearings with its neighbors. The control design relies on a non-singular extraction algorithm for separate design of translation and rotation control. The outer loop of the control scheme utilizes a filter-like approach to overcome the lack of bearing rate measurements in the bearing-only formation controller. Moreover, employing differentiators following the separation principle with properties of asymptotic high accuracy, a uniform differentiator is provided for each following quadrotor to overcome the absence of linear velocity and acceleration feedback in the inner-loop controller. Ultimately, the efficacy of the proposed control strategy is validated through a combination of Lyapunov stability theory and extensive numerical simulations.