Multi-Robot Bearing-only Pose Estimation via Angle Rigidity
For multi-robot systems, this work relaxes the sensing topology requirement from bearing rigidity to angle rigidity, enabling pose estimation in more practical scenarios.
This paper proposes a distributed bearing-based pose estimator for multi-robot systems that uses angle rigidity, a weaker condition than bearing rigidity, to estimate positions and orientations in 3D without prior orientation knowledge. The observer achieves local uniform exponential stability under persistently exciting motions, validated through simulations.
This letter proposes a novel distributed bearing-based pose estimator for time-varying multi-robot systems. The method uses angles computed from body-frame bearings to estimate the robots' positions in $\mathbb{R}^3$ without knowledge of their orientations. The orientations in $\mathrm{SO}(3)$ are recovered from the estimated positions, the bearings, and the bearing derivatives. The proposed observer only requires the (directed) sensing topology to be \textit{angle-rigid}, a weaker condition than the commonly used ones like bearing rigidity. Local uniform exponential stability of the proposed observer is established under the assumption of persistently exciting motions for a subset of robots. Simulations are presented and discussed to evaluate the scheme's effectiveness and practicality.