Move First, Commit Later: Selective LiDAR-to-BIM Global Initialization via Sequential Consensus with Symmetry-Aware Abstention
Robotics
Summary
The authors address the challenge of correctly placing a robot inside a building model when the building has many similar-looking rooms that can cause confusion. They propose a method called "Move First, Commit Later" that waits to decide where exactly the robot is until enough evidence is gathered, avoiding wrong confident guesses caused by symmetrical layouts. Their approach combines information from multiple scans and uses building topology just to check if a position is possible. Tests show that their method avoids errors and accurately estimates the robot’s location better than usual approaches, and it can work with different scanning systems.
Authors
Yujie Zhang, Yuxuan Guo, Jiashuo Zheng, Zeheng Fan, Xiaohui Jia, Jinyue Liu
Abstract
Global LiDAR-to-BIM initialization must place a robot within an as-designed building model without a prior pose. In repetitive interiors, the principal failure mode is not low-confidence registration but confident aliasing: a submap can match several BIM regions with comparable scores, producing a high-scoring pose displaced by symmetry. We present Move First, Commit Later, a selective layer that treats a registration front-end as an evidence source and decides whether to commit. Candidates from multiple submaps are mapped to a common $\mathrm{SE}(2)$ anchor; a top-1 consensus $B_m$, invariant to non-champion multiplicity, aggregates cross-submap evidence; and topology serves only as a binary feasibility gate. The decision is typed--COMMIT, DEFER, or AMBIGUOUS($τ$), reporting the detected symmetry period--and reversible: symmetry-breaking motion upgrades AMBIGUOUS to COMMIT. On a real multi-room building and a controlled symmetric simulation, the layer commits correctly in every tested trajectory-scale configuration and otherwise abstains with a typed state, whereas forced-choice policies on the same front-end select wrong rooms in most cases. Committed anchors are within 0.02--0.36 m of an independent laser-tracker position reference and within $1.9^\circ$ of a BIM-registration orientation proxy. The evaluation covers one building and one front-end; the layer is designed to be front-end modular.