We consider the problem of distributed attitude estimation of multi-agent systems, evolving on SO(3), relying on individual angular velocity and relative attitude measurements. We propose a nonlinear distributed hybrid attitude estimation scheme guaranteeing global asymptotic convergence of the attitude estimation errors to a common constant orientation, under an undirected, connected and acyclic graph topology. Moreover, in the presence of a leader in the group (knowing its absolute orientation), one can guarantee global asymptotic convergence of the attitude estimation errors to zero. Numerical simulation results are presented to illustrate the performance of our proposed scheme.

In this paper, we address the problem of attitude synchronization for a group of rigid body systems evolving on SO(3). The interaction among these systems is modeled through an undirected, connected, and acyclic graph topology. First, we present an almost global continuous distributed attitude synchronization scheme with rigorously proven stability guarantees. Thereafter, we propose two global distributed hybrid attitude synchronization schemes on SO(3). The first scheme is a hybrid control law that leverages angular velocities and relative orientations to achieve global alignment to a common orientation. The second scheme eliminates the dependence on angular velocities by introducing dynamic auxiliary variables, while ensuring global asymptotic attitude synchronization. This velocity-free control scheme relies exclusively on attitude information. The proposed schemes are applicable to heterogeneous multi-agent systems, where agents may have distinct inertia matrices. Simulation results are provided to illustrate the effectiveness of the proposed distributed attitude synchronization schemes.

In this paper, we address the attitude alignment problem for a group of rigid body systems evolving on $SO(3)$ under an undirected, connected and acyclic communication graph topology. We propose a velocity-free distributed hybrid feedback control law, relying on the relative orientations, with global asymptotic stability guarantees. Numerical simulation results are presented to illustrate the performance of the proposed distributed hybrid feedback control law.

In this letter, we address the distributed pose estimation problem for multi-agent systems under a directed graph topology, where two agents have access to their respective poses, and the other agents have unknown static positions and time-varying orientations. The proposed estimation scheme consists of two cascaded distributed observers, an almost globally asymptotically stable (AGAS) attitude observer and an input-to-state stable (ISS) position observer, leading to an overall AGAS distributed localization scheme. Numerical simulation results are presented to illustrate the performance of our proposed distributed pose estimation scheme.

In this paper, we consider the problem of distributed pose estimation of multi-vehicle networks, with a leader-follower structure evolving on $SO(3) \times {\mathbb{R}^3},$ relying on individual linear and angular velocity measurements as well as local inter-vehicle time-varying bearing measurements. We propose a cascaded nonlinear distributed pose estimation scheme where the estimated attitude obtained from an exponentially stable observer is fed to an input-to-state stable position estimation scheme, leading to an overall pose estimation scheme enjoying an exponential stability property.Numerical simulation results are presented to illustrate the performance of the proposed estimation scheme.