Navigating unstructured environments requires assessing traversal risk relative to a robot's physical capabilities, a challenge that varies across embodiments. We present CATNAV, a cost-aware traversability navigation framework that leverages multimodal LLMs for zero-shot, embodiment-aware costmap generation without task-specific training. We introduce a visuosemantic caching mechanism that detects scene novelty and reuses prior risk assessments for semantically similar frames, reducing online VLM queries by 85.7%. Furthermore, we introduce a VLM-based trajectory selection module that evaluates proposals through visual reasoning to choose the safest path given behavioral constraints. We evaluate CATNAV on a quadruped robot across indoor and outdoor unstructured environments, comparing against state-of-the-art vision-language-action baselines. Across five navigation tasks, CATNAV achieves 10 percentage point higher average goal-reaching rate and 33% fewer behavioral constraint violations.
@article{arxiv.2603.22800,
title = {CATNAV: Cached Vision-Language Traversability for Efficient Zero-Shot Robot Navigation},
author = {Aditya Potnis and Francisco Affonso and Shreya Gummadi and Naveen Kumar Uppalapati and Girish Chowdhary},
journal= {arXiv preprint arXiv:2603.22800},
year = {2026}
}