Global Finite-Time Attitude Consensus of Leader-Following Spacecraft Systems Based on Distributed Observers

TL;DR

This paper proposes a novel distributed observer and hybrid controller for spacecraft attitude consensus, achieving finite-time convergence and global consensus on the attitude manifold under certain network conditions.

Contribution

It introduces a second-order sliding mode observer for finite-time state estimation and extends quaternion-based controllers for leader-following attitude consensus.

Findings

Finite-time convergence of attitude estimates.

Global attitude consensus achieved.

Effective under both full-state and attitude-only measurements.

Abstract

This paper addresses the leader-following attitude consensus problem for a group of spacecraft when at least one follower can access the leader's attitude and velocity relative to the inertial space. A nonlinear distributed observer is designed to estimate the leader's states for each follower. The observer possesses one important and novel feature of keeping attitude and angular velocity estimation errors on second-order sliding modes, and thus provides finite-time convergent estimates for each follower. Further, quaternion-based hybrid homogeneous controllers recently developed for single spacecraft are extended and then applied, by establishing a separation principle with the proposed observer, to track the leader's attitude motion. As a result, global finite-time attitude consensus is achieved on the entire attitude manifold, with either full-state measurements or attitude-only measurements, as long as the network topology among the followers is undirected and connected. Numerical simulations are presented to demonstrate the performance of the proposed methods.