Angle-based Localization and Rigidity Maintenance Control for Multi-Robot Networks
It provides a theoretical foundation and practical control method for angle-based localization and rigidity maintenance in multi-robot systems, addressing sensing constraints and switching topologies.
This paper establishes the relationship between angle rigidity and bearing rigidity for multi-robot networks and proposes a distributed angle-based localization scheme with local exponential stability under switching sensing graphs. It also introduces a decentralized gradient-based controller for rigidity maintenance, validated through simulations.
In this work, we study angle-based localization and rigidity maintenance control for multi-robot networks. First, we establish the relationship between angle rigidity and bearing rigidity considering \textit{directed} sensing graphs and \textit{body-frame} bearing measurements in both $2$ and $3$-\textit{dimensional space}. In particular, we demonstrate that a framework in $\mathrm{SE}(d)$ is infinitesimally bearing rigid if and only if it is infinitesimally angle rigid and each robot obtains at least $d-1$ bearing measurements ($d \in \{2, 3\}$). Building on these findings, this paper proposes a distributed angle-based localization scheme and establishes local exponential stability under switching sensing graphs, requiring only infinitesimal angle rigidity across the visited topologies. Then, since the set of available angles strongly depends on the robots' spatial configuration due to sensing constraints, we investigate rigidity maintenance control. The \textit{angle rigidity eigenvalue} is presented as a metric for the degree of rigidity. A decentralized gradient-based controller capable of executing mission-specific commands while maintaining a sufficient level of angle rigidity is proposed. Simulations were conducted to evaluate the scheme's effectiveness and practicality.